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XVI INTERDISCIPLINARY RESEARCH PROGRAM I n t e r d i s c i p l i n a r y Research
INTERDISCIPLINARY RESEARCH PROGRAM Page Organization of the Committee 665 Summary of Committee A c t i o n s 665 P r o j e c t O b j e c t i v e s and R e s u l t s 665 20.1 A n a l y s i s of G r a v i t y Observations 666 20.2 C r u s t a l S t r u c t u r e Determinations Using G r a v i t y and Seismic T r a v e l Time Measurements 670 20.3 Study of Marine Seismic Data 673 20.4 Study of Long P e r i o d & Extensometer Data 677 20.5 A n a l y t i c a l Studies of C r u s t a l S t r u c t u r e 678 20.6 A n a l y s i s of IGY A r c t i c , A n t a r c t i c , and P a c i f i c Records 679 20.7 A n a l y s i s of IGY Land & Sea G r a v i t y & Seismic Data 682 21.1 A n a l y s i s of CO2 Data 686 21.2 T h e o r e t i c a l Study of Ozone Data 688 21.3 A n t a r c t i c Atmospheric-Oceanographic-Glaciologic I n t e r a c t i o n s . . . 690 21.4 P o l a r Stratosphere S t r u c t u r e , C i r c u l a t i o n & Ozone D i s t r i b u t i o n . . 697 21.5 A n a l y s i s of IGY Oceanographic Data 702 21.6 A n a l y s i s of IGY Oceanographic Data 710 21.7 A n a l y s i s of IGY Oceanographic Data 712 21.8 A n a l y s i s of IGY Oceanographic Data 718 21.9 A n a l y s i s of Atmospheric and Oceanological Data 720 21.10 P o l a r Vortex Studies 723 21 11 A n a l y s i s of Blue G l a c i e r Micrometeorological Records 726 21.12 A n t a r c t i c I c e Accumulation Study 728 21.13 A n a l y s i s of A n t a r c t i c Micrometeorological Data 730 21.14 A n a l y s i s of Heat Budget Data of S t a t i o n Alpha 734 21.15 A n a l y s i s of G l a c i a l G e o l o g i c a l Data from Spitsbergen 737 22.1 Ionospheric Dynamics 739 22.2 A n a l y s i s of S o l a r Phenomena & Radio Noise 741 22.3 S o l a r F l a r e Studies 744 22.4 Study of F l a r e Spectra 747 22.5 V a r i a t i o n of Cosmic Rays i n the P o l a r Regions 748 22.6 A n a l y s i s of IGY Data from A l a s k a 750 22.7 T h e o r e t i c a l Studies of Upper Atmosphere Data 755 22.8 A n a l y s i s of IGY Upper Atmosphere Data 758 22.9 A n a l y s i s of F Region Ionospheric Data 759 22.10 A n a l y s i s of Ionospheric B a c k s c a t t e r Data 762 22.11 A n a l y s i s of Synoptic Cosmic Ray Data 764 22.12 A n a l y s i s of L i n e I s l a n d Geomagnetic Data 766 22.13 Study of E q u a t o r i a l Enhancement of T r a n s i e n t s and A c t i v i t y P a t t e r n s & Magnetic Storn Onsets a t Pol a r L a t i t u d e s . . . 768 22.14 A n a l y s i s of Balloon Data 769 22.15 A n a l y s i s of Synoptic Cosmic Rays Data 771 22.16 Research i n S o l a r & S o l a r - T e r r e s t r i a l Problems 773 22.17 Charged P a r t i c l e O r b i t s i n the Geomagnetic F i e l d 774 23.1 S p e c i a l Research Surveys by D i s t i n g u i s h e d S c i e n t i s t s from Abroad 775 23.2 V i s i t i n g S c i e n t i s t s Program 778 664
XVI. INTERDISCIPLINARY RESEARCH PROGRAM A. Organization of the Committee The USNC Exec u t i v e Committee decided to organize a committee to review proposals f o r a n a l y s i s of IGY data and requested M.M. Shapiro to serve as Chairman; B. Haurwitz, Frank Press and E.H. V e s t i n e were appointed members of the committee and A.H. Shapley, M.A. Tuve and Harry Wexler were e x - o f f i c i o members r e p r e s e n t i n g the USNC Ex e c u t i v e Committee. One meeting of the committee was held on October 11, 1958; Harry Hess a t - tended t h i s meeting as an a l t e r n a t e to Frank P r e s s , who could not attend but commented by m a i l on the proposals. B. Summary of Committee A c t i o n s The Committee, a c t i n g under the d e c i s i o n by the USNC Exec u t i v e Comiftittee t h a t t h i s a n a l y s i s program should be l i m i t e d to m u l t i - d i s c i p l i n e s t u d i e s of IGY data, reviewed proposals by the v a r i o u s i n s t i t u t i o n s t h a t had p a r t i c i p a t e d i n the IGY o b s e r v a t i o n a l program and determined the appropriate l e v e l of support that could be extended under the t o t a l funds a l l o c a t e d to t h i s program. I n a d d i t i o n , i t was decided to encourage proposals from some i n s t i t u t i o n s that had not p a r t i c i p a t e d d i r e c t l y i n the IGY o b s e r v a t i o n a l program but a t which there were a c t i v e r e s e a r c h s c i e n t i s t s working m appropriate s c i e n t i f i c a r e a s . I t was a l s o de- cided to e s t a b l i s h some s p e c i a l p r o j e c t s to support several-month v i s i t s to the United S t a t e s of d i s t i n g u i s h e d s c i e n t i s t s from other c o u n t r i e s to work w i t h c o l l e a g u e s i n r e - sear c h i n s t i t u t i o n s and a t the va r i o u s u n i t s of World Data Center A f o r the purpose of s t i m u l a t i n g i n t e r e s t i n the i n t e r d i s c i p l i n a r y a n a l y s i s of IGY data. C. P r o j e c t O b j e c t i v e s and R e s u l t s P r o j e c t s i n the i n t e r d i s c i p l i n a r y r e s e a r c h program were arranged i n four groups as fo l l o w s : C r u s t and Core P r o j e c t 20 S e r i e s Heat and Water P r o j e c t 21 S e r i e s Upper Atmosphere P r o j e c t 22 S e r i e s S p e c i a l Research P r o j e c t 23 S e r i e s 665
INTERDISCIPLINARY RESEARCH P r o j e c t 20.1 - A n a l y s i s of G r a v i t y Observations 1. O b j e c t i v e s . T h i s p r o j e c t a t the Dept. of Geology, U n i v e r s i t y of Wisconsin, provided f o r the study and g e o l o g i c a l i n t e r p r e t a t i o n of the g r a v i t y observations taken under the IGY, i n p a r t i c u l a r those from p r o j e c t s 5.7, 5.8, and from the v a r i o u s a n t a r c t i c p r o j e c t s . I t was planned to: a. Determine g r a v i t y values on an absolute datum ( r e f e r r e d to Potsdam); b. Determine the p r i n c i p a l f a c t s for each g r a v i t y l o c a t i o n ( i d e n t i f i c a t i o n , l a t i t u d e , longitude, observed g r a v i t y , t h e o r e t i c a l g r a v i t y r e f e r r e d to sea l e v e l , f r e e - a i r anomaly, and simple Bouguer anomaly), c. Prepare d e s c r i p t i o n s of base s i t e s throughout the world that have been i n t e - grated i n t o the program; d. I n t e g r a t e g r a v i t y data taken by commercial ge o p h y s i c a l work, where f e a s i b l e , e. Tabulate and reproduce v a l u e s , f. Prepare isoanomaly maps based on f r e e - a i r anomalies f o r geodetic r e s e a r c h , Bouguer maps f o r g e o l o g i c a l s t u d i e s , and s i m p l i f i e d i s o s t a t i c anomaly maps; g. C a r r y out a n a l y t i c a l s t u d i e s p e r t a i n i n g to v a r i a t i o n s m e a r t h c r u s t a l s t r u c t u r e and the r e l a t i o n s h i p to s e i s m i c data and s u r f i c i a l geology, and g e o i d a l v a r i a t i o n s . 2. Operations. Approximately 60,000 observations and a d d i t i o n a l 150,000 anomaly va l u e s r e s u l t e d from the v a r i o u s IGY g r a v i t y programs; i t was r e q u i r e d to compute observed gra- v i t y values from the raw o b s e r v a t i o n s , compute e l e v a t i o n c o n t r o l s , check p o s i t i o n con- t r o l s , e t c . The data were prepared f o r storage and f u r t h e r a n a l y s i s on punched cards and programs were prepared f o r machine a n a l y s i s . 3. Personnel. G.P. Woollard was p r o j e c t d i r e c t o r , a s s o c i a t e d w i t h him i n t h i s work were John Rose, Robert I v e r s o n , Thomas S. Landon, Ned Ostenso, James Sparkman, John Behrendt, Oscar Strickholm, Richard L o n g f i e l d , James Weinman, Edward T h i e l , C h a r l e s Bentley, and D e l i a L a v i n . 4. Data. The f i n a l v alues of data for the i n t e r n a t i o n a l bases occupied, w i t h a l l necessary c o r o l l a r y information, was published i n a monograph (see b i b l i o g r a p h y below), copies of which were supplied to the g r a v i t y world data c e n t e r s . T h i s p u b l i c a t i o n a l s o shows the a r e a l coverage by s t a t e i n the United S t a t e s , w i t h 20-mgal Bouguer anomaly contours. A composite map of the country on a s c a l e of 1:2,500,000 w i t h 10-mgal con- tours has been prepared and w i l l be published by the U.S. G e o l o g i c a l Survey. A separate b i - l i n g u a l p u b l i c a t i o n covering C e n t r a l and South America i s i n p r e p a r a t i o n . 5. R e s u l t s . As an example of the use of g r a v i t y data m connection w i t h other i n f o r - mation p e r t a i n i n g to g e o l o g i c a l s t u d i e s , the a n a l y s i s of data i n the A n t a r c t i c permitted i n f e r e n c e s about the s u b g l a c i a l rock s u r f a c e and c r u s t a l s t r u c t u r e , t h i s work i s r e l a t e d to the s e i s m i c data r e p o r t i n p r o j e c t 11.7. a. C r u s t a l S t r u c t u r e i n A n t a r c t i c a . The g r a v i t y r e s u l t s can be used not only to provide d e t a i l on the i c e - t h i c k n e s s p r o f i l e but a l s o to o b t a i n a rough p i c t u r e of the c r u s t a l s t r u c t u r e underlying the A n t a r c t i c Continent. To remove v a r i a t i o n s due to l o c a l changes i n the e l e v a t i o n of the rock s u r f a c e , the f r e e - a i r g r a v i t y anomalies were averaged over 100 km i n t e r v a l s . The r e s u l t i n g anomaly p a t t e r n shows t h a t , by and l a r g e . West A n t a r c t i c a i s m i s o s t a t i c balance, the average anomalies ranging between -52 and +49 mgals. The o v e r a l l mean anomaly of -9 mgals i s not s i g n i f i c a n t when compared w i t h the root mean d e v i a t i o n from the mean of t mgals. S i m i l a r r e s u l t s are obtained for E a s t A n t a r c t i c a w i t h the more r e s t r i c t e d amount of data a v a i l a b l e . 666
INTERDISCIPLINARY RESEARCH I30*W IIO'W 60'W 70*W 40*W 30'W I80*W 1 7 0 ' E I S O ' E SHAUS BYRD ELLSWORTH I C E S H E L F W E S T A N T A R C T I C A E L E V A T I O N OF MOHOROVICIC DISCONTINUITY IN KM (FROM BOUGUER G R A V I T Y ) CONTOUR I N T E R V A L - 2 KM CMURDO S C A L E I S O ' E I 2 0 * E I I O ' E l O O ' E F i g u r e 1. E l e v a t i o n s of the Mohorovicic d i s c o n t i n u i t y ( i n k i l o m e t e r s ) , 667
INTERDISCIPLINARY RESEARCH The d i s c o v e r y that most of the land s u r f a c e under the i c e of West A n t a r c t i c a l i e s w e l l below sea l e v e l has made i t of p a r t i c u l a r i n t e r e s t to estimate c r u s t a l t h i c k - ness i n the a r e a . T h i s has been done by u s i n g e m p i r i c a l r e l a t i o n s which r e l a t e the e l e v a t i o n of the Mohorovicic d i s c o n t i n u i t y (M) to s u r f a c e e l e v a t i o n s and the Bouguer g r a v i t y anomalies, r e s p e c t i v e l y . I t i s assumed that only f e a t u r e s 160 km or more i n l i n e a r extent could normally be expected to achieve i s o s t a t i c balance. To a l l o w for t h i s and a l s o to minimize the e f f e c t of l o c a l departures of Bouguer anomalies and e l e - v a t i o n s from the r e g i o n a l v a l u e s , both were averaged over i n t e r v a l s of not l e s s than 400 km. Since the r e l a t i o n between s u r f a c e h e i g h t s , and the e l e v a t i o n of M given by Woollard i s based on a normal c r u s t w i t h the s u r f i c i a l rocks having mean d e n s i t y of 2.67 gm/cc, eq u i v a l e n t s u r f a c e e l e v a t i o n s i n A n t a r c t i c a were found by condensing the i c e column to i t s e q u i v a l e n t mass of s u r f i c i a l rock m a t e r i a l . E l e v a t i o n s of M obtained from Bouguer anomalies (Mb) and from s u r f a c e e l e v a t i o n s (Me) have both been computed and found to be i n c l o s e agreement, d i f f e r i n g by an average of only 0.5 km. S i n c e the v a l u e s of Me a r e based d i r e c t l y on the assumption of i s o s t a t i c e q u i l i b r i u m , whereas those of Mb depend upon the observed g r a v i t y v a l u e s , the agreement between Mb and Me provides f u r t h e r evidence that West A n t a r c t i c a i s i n g e n e r a l i s o s t a t i c balance. A contour map based on the values of Mb i s shown i n F i g . 1. The deep bedrock channel, l y i n g 5 km below the i c e s u r f a c e , i s marked by a c o n s i s t e n t l y t h i n c r u s t , and the M e l e v a t i o n under t h i s channel i n Marie Byrd Land i s only s l i g h t l y deeper than i t I S under the Ross I c e S h e l f . The trend of a t h i n c r u s t , northeast from Bryd s t a t i o n , supports the i n f e r e n c e drawn from the s u b g l a c i a l topography that the channel extends to the B e l l i n g s h a u s e n Sea. b. The R e l a t i o n s between I s o s t a t i c G r a v i t y Anomalies, C r u s t a l S t r u c t u r e and Composition m the United S t a t e s . On examination of c r u s t a l s t r u c t u r e and composition as d e l i n e a t e d by s e i s m i c r e f r a c t i o n s t u d i e s of the c r u s t , the a s s o c i a t e d geology and g r a v i t y anomaly values i n d i c a t e t h a t apparent departure from i s o s t a t i c e q u i l i b r i u m are r e l a t e d p r i n c i p a l l y to ( i ) v a r i a t i o n s i n the l i t h o l o g i c composition of the c r u s t , ( i i ) the s u r f a c e and n e a r - s u r f a c e geology, and ( i i i ) r e g i o n a l r a t h e r than l o c a l compen- s a t i o n for the s u r f a c e topography. I n very few areas does i t appear that a f i r m case can be made f o r non-hydrostatic e q u i l i b r i u m i f i t i s assumed t h a t the c r u s t i s supported by denser p l a s t i c mantle m a t e r i a l . I n a l l a r e a s of p o s i t i v e i s o s t a t i c anomalies st u d i e d s e i s m i c a l l y to date, i t i s found that the c r u s t has an apparent greater-than-normal d e n s i t y as i n d i c a t e d by high s e i s m i c v e l o c i t y v a l u e s and a g r e a t e r t h i c k n e s s than would normally be deduced from the s u r f a c e e l e v a t i o n , Bouguer g r a v i t y anomalies or i s o s t a t i c anomalies. An a r e a of p o s s i b l e exception, which has not y e t been stu d i e d s e i s m i c a l l y , i s the middle Rocky Mountain r e g i o n where p o s i t i v e i s o s t a t i c anomalies a s s o c i a t e d w i t h areas of geologic u p l i f t appear to be r e l a t e d i n large measure to an absence of l o c a l compensation. Areas of negative i s o s t a t i c anomaly, c o r r e c t e d for the e f f e c t of the s u r f a c e geology i n many p l a c e s , appear to be r e l a t e d to a c r u s t of lower-than-normal d e n s i t y and t h i c k n e s s r a t h e r than to a t h i c k c r u s t . By a combined use of Bouguer and i s o s t a t i c anomalies, i t appears p o s s i b l e to deduce w i t h reasonable a c c u r a c y ( t 10 per c e n t ) the t h i c k n e s s and to some extent the composition of the c r u s t i n any a r e a where a r e a l i s t i c c o r r e c t i o n can be made f o r the e f f e c t of the s u r f a c e geology on the g r a v i t y v a l u e s . c. An E v a l u a t i o n of the World's G r a v i t y C o n t r o l . Using both pendulums and g r a v i - meters over the past ten y e a r s , t i e s have been e f f e c t e d to most of the f i r s t - o r d e r g r a v i t y bases designated by the I n t e r n a t i o n a l G r a v i m e t r i c Bureau as w e l l as to v a r i o u s n a t i o n a l bases. The pendulum data, worked up independently and evaluated along w i t h other pendulum data, have served as a b a s i s for c a l i b r a t i n g the gravimeters used. Com- parisons of g r a v i t y values on the Potsdam system a t the v a r i o u s bases and the g r a v i t y i n t e r v a l s between bases, as determined from the pendulum observations and gravimeter measurements, show that the world network now has a general r e l i a b i l i t y of about tO.3 mgal, although some bases are s t i l l apparently i n e r r o r by over 1 mgal. Comparisons of 668
INTERDISCIPLINARY RESEARCH g r a v i t y v a l u e s determined by other i n v e s t i g a t o r s , both a t the pendulum bases and a t other bases throughout the world, i n d i c a t e that most such gravimeter work i s good i f d i f f e r e n c e s i n c a l i b r a t i o n standards are taken i n t o c o n s i d e r a t i o n . T h i s a p p l i e s to work done w i t h gravimeters having a high and v a r i a b l e d r i f t r a t e as w e l l as that done with ' d r i f t l e s s ' meters. The l a r g e s t cause of random v a r i a t i o n s that may amount to over 1 ragal appears to be r e l a t e d to the screw of the reading d i a l and to the d i v i d i n g - head i n a c c u r a c i e s i n s c r i b i n g the reading d i a l . The e v a l u a t i o n of the v a r i o u s i n t e r n a - t i o n a l g r a v i t y s t a n d a r d i z a t i o n ranges e s t a b l i s h e d w i t h pendulums over the IGY period shows no d i f f e r e n c e i n c a l i b r a t i o n f a c t o r s between the v a r i o u s ranges. 6. Bibliography. a. Papers Presented a t Meetings. G.P. Woollard. "The R e l a t i o n Between Anomalies, C r u s t a l S t r u c t u r e and Com- p o s i t i o n i n the United S t a t e s . " F o r t y - f i r s t Ann. Meeting, AGU, Washington, D.C., A p r i l 1960, G.P. Woollard and J.C. Rose "An E v a l u a t i o n of the World's G r a v i t y C o n t r o l . " Forty-second Ann. Meeting, AGU, Washington, D.C., A p r i l 1961. b. Published Papers. G.P. Woollard and J.C. Rose: " R e s u l t s for a G r a v i t y C o n t r o l Network a t A i r - ports m the United S t a t e s . " Geophysics, v o l . 23, no. 3, 1958, pp. 520-35. G.P. Woollard and J.C. Rose. "Pendulum and Gravimeter Measurements of E a r t h ' s G r a v i t y . " IGY B u l l . No. 17. 1958, pp. 5-11. G.P. Woollard and J.C. Rose- " G r a v i t y Observations during the IGY." Geophys. Monogr. No. 2, Geophysics and the IGY, Amer. Geophys. Un., 1958, pp. 198-202. G.P. Woollard " C r u s t a l S t r u c t u r e from G r a v i t y and Seismic Measurements," J . Geophys. Res., v o l . 64, no. 10, 1959, pp. 1521-44. J.C. Behrendt and G.P. Woollard: "An E v a l u a t i o n of the G r a v i t y C o n t r o l Network i n North America." Geophysics, v o l . 26, no. 1, 1961, pp. 57-78. G.P. Woollard: " C r u s t a l S t r u c t u r e m A n t a r c t i c a . " Geophys. Monogr. No. 7, A n t a r c t i c Research, AGU, 1962, pp. 53-73. G.P. Woollard and J.C. Rose: " I n t e r n a t i o n a l G r a v i t y Measurements." Soc. E x p l . G e o p h y s i c i s t s , 1963, 518 pp. 669
INTERDISCIPLINARY RESEARCH P r o j e c t 20.2 - C r u s t a l S t r u c t u r e Determinations Using G r a v i t y and Seismic T r a v e l Time Measurements 1. O b j e c t i v e s . T h i s p r o j e c t a t the Dept. of Geology, U n i v e r s i t y of Wisconsin, had the following o b j e c t i v e s a. To r e - e v a l u a t e the s e i s m i c b l a s t r e s u l t s obtained by e a r l i e r i n v e s t i g a t o r s through re-study of the o r i g i n a l records ( p a r t i c u l a r l y as regards second a r r i v a l s ) and through recomputation of depths, i n c o r p o r a t i n g i n part s y n t h e t i c time and depth para- meters based on w e l l or other geophysical data that w i l l allow a t l e a s t for the s u r f i c i a l geology that was neglected i n some of the e a r l i e r work, b. To perform a n a l y t i c a l s t u d i e s of g r a v i t y data for these same a r e a s ; c. To c o r r e l a t e the r e s u l t s m terms of the geologic s e t t i n g ; d. To extend these r e s u l t s i n t o a r e a s where only geologic and g r a v i t y data are a v a l l a b l e . 2. Operations. U n i v e r s i t y of Wisconsin s c i e n t i s t s c a r r i e d out s p e c i a l d e t a i l e d s e i s m i c measurements as w e l l as a n a l y t i c a l s t u d i e s to a s c e r t a i n how much of the d i s - crepancy between the two methods of c r u s t a l s t r u c t u r e determination could be r e l a t e d to such f a c t o r s as- the techniques of s e i s m i c measurement and r e d u c t i o n used, e f f e c t of the s u r f i c i a l geology, geologic s t r u c t u r a l g r a i n w i t h i n the c r y s t a l l i n e rock complex, slope of r e f r a c t i o n horizons, and the importance of masked l a y e r s represented only by second a r r i v a l s . A l l of these f a c t o r s were found to be s i g n i f i c a n t , and taken i n toto made an a p p r e c i a b l e d i f f e r e n c e i n the s e i s m i c depths computed. The measurements con- ducted a l s o showed that where d e t a i l was a v a i l a b l e , the c r u s t a l s t r u c t u r a l composition i n d i c a t e d could be r e c o n c i l e d w i t h the g r a v i t y data. The area studied included the high p l a t e a u of Mexico, c h a r a c t e r i z e d by negative i s o s t a t i c g r a v i t y anomalies, the low p l a i n s over the M i s s i s s i p p i Embayment, the middle Rocky Mountains, the high p l a i n s a r ea immediately adjacent on the E a s t , c h a r a c t e r i z e d by p o s i t i v e i s o s t a t i c g r a v i t y anomalies; and the Wisconsin U p l i f t , c h a r a c t e r i z e d by negative i s o s t a t i c anomalies. 3. Personnel. T h i s work was under the d i r e c t i o n of G.P. Woollard, a s s o c i a t e d w i t h him were John S t e i n h a r t , R.P. Meyer, W.E. B o n i n i , Joseph Laurence, Noel Thompson, K e i t h McComy, T . J . Smith, F.L. Novachek, Richard Wold, David Schlabach, F o r r e s t Dowling, and Perry Parks, 4. R e s u l t s . The r e s u l t s for most of these s t u d i e s are summarized i n " E x p l o s i o n Studies of C o n t i n e n t a l S t r u c t u r e " , a monograph published by the Carnegie I n s t i t u t i o n of Washing- ton. The f o l l o w i n g examples i l l u s t r a t e some of the r e s u l t s . a. P r e l i m i n a r y R e s u l t s of C r u s t a l Studies i n E a s t e r n Montana. Continuous p r o f i l e s from 100 to 250 km have been obtained as p a r t of a 300-km r e s e r v e d - s e i s m i c - r e f r a c t i o n p r o f i l e l o c ated i n the northern Great P l a i n s and the Powder R i v e r B a s i n extending north from Sheridan, Wyoming, to the v i c i n i t y of the F o r t Peck r e s e r v o i r m Montana. The Bouguer anomalies average about -100 mgals. P r i n c i p a l phases a r e , i n g e n e r a l , repre- sented on a l l records as primary or secondary events. Secondary events not d i r e c t l y r e l a t e d to r e f l e c t i o n and r e f r a c t i o n events are present. B a s i c r e s u l t s for the h i g h l y d e t a i l e d south-to-north l i n e s are e n t i r e l y compatible w i t h a north-to-south reconnaissance l i n e completing the r e v e r s e . S t a n d a r d i z a t i o n of instruments ( a m p l i f i e r s , geophones, and paper speed) used i n the work, and water shooting, have apparently contributed s i g n i f i - c a n t l y to the uniform c h a r a c t e r of records made a t d i f f e r e n t times and on v a r y i n g t e r r a i n s . Apparent v e l o c i t i e s computed for spreads of from 4500 to 6000 f e e t i n length are u s u a l l y compatible w i t h or i n d i c a t e higher v e l o c i t i e s than the gross t r a v e l - t i m e v e l o c i t y and are of r e a l a s s i s t a n c e i n i d e n t i f y i n g a r r i v a l s . P r e l i m i n a r y r e s u l t s i n d i c a t e v e l o c i t y t h i c k - ness r e l a t i o n s as 1.76 km or 2.75 km/sec m a t e r i a l , 1.6 km of 4.65 km/sec m a t e r i a l , 23.63 km of 6.15 km/sec m a t e r i a l , and 21.40 km of 7.37 km/sec m a t e r i a l , w i t h a Mohorovicic 670
INTERDISCIPLINARY RESEARCH d i s c o n t i n u i t y represented by a v e l o c i t y of 8.11 km/sec. Over the eastern p o r t i o n , a sub-M layer w i t h a v e l o c i t y of 9.05 km/sec was characterized at depths ranging from 15 t o 20 km below the M horizon. The t o t a l c r u s t a l thickness i s 48.4 km. A l l layers are e s s e n t i a l l y f l a t l y i n g . b. S t a t i s t i c a l Uncertainty and I n t e r p r e t a t i o n Problems i n Seismic Crustal Studies w i t h A p p l i c a t i o n s . I n t e r p r e t a t i o n of c r u s t a l seismic r e s u l t s i s a problem of f i n d i n g a model th a t f i t s the data as c l o s e l y as possible. I n many cases a number of pla u s i b l e models may be postulated and c r i t e r i a are then needed f o r r e j e c t i n g some of these models and f o r evaluating the l i k e l i h o o d of the remaining models. By expanding the depth func- t i o n i n a Taylor series i n the area of the experimental values, s t r a i g h t f o r w a r d s t a t i s - t i c a l e valuation of unc e r t a i n t y may be made. The d i s t r i b u t i o n of residuals obtained by a large number of i n v e s t i g a t o r s i s symmetric, and least-squares techniques are thus j u s t i f i e d . At l e a s t an estimate of minimum u n c e r t a i n t y can be obtained i n t h i s way. This method i s of value f o r comparing c r u s t a l r e s u l t s from d i f f e r e n t areas and experi- menters. A valuable c r i t e r i o n f o r accepting or r e j e c t i n g some of the pla u s i b l e models from r e f r a c t i o n data i s the r e f l e c t i o n amplitudes. The r e f l e c t i o n t r a v e l times are computed f o r the various models and amplitudes measured from the seismograms a t the predicted times. The observed amplitude v a r i a t i o n w i t h distance i s compared w i t h the shape of the t h e o r e t i c a l curve. Some models w i l l f a i l to s a t i s f y t h i s t e s t . I f the magnitude of the energy source i s not known, use of amplitude r a t i o s i s recommended. A p p l i c a t i o n of the methods given above i s shown f o r a c r u s t a l seismic study i n the c e n t r a l plateau of Mexico. Four models were postulated and were found to f i t the data reasonably w e l l . The s t a t i s t i c a l technique showed th a t the data were i n s u f f i c i e n t f o r a d i s t i n c t i o n to be made between two of the models. The other two models were discarded as being widely a t variance w i t h the predicted r e f l e c t i o n amplitudes. The favored model consists of 4.2 km of surface m a t e r i a l , 28.5 km of 6.10 km/sec m a t e r i a l , 10.2 km of 7.63 km/sec m a t e r i a l , and a v e l o c i t y of 8.28 km/sec f o r the upper mantle. There i s some evidence of a v e l o c i t y increase m the 6.10 km layer. c. Linear Analysis of the Results of Explosion Seismic Measurements on the Conti- nents. Relationships between c r u s t a l thickness, g r a v i t y anomalies, e l e v a t i o n , and observed v e l o c i t i e s have been reported or postulated i n recent years. To as c e r t a i n whether some or a l l of these r e l a t i o n s h i p s were supported by the data from explosion seismology on the continents, r e s u l t s of 73 measurements of c r u s t a l thickness were subjected to simple and m u l t i p l e l i n e a r regression analysis. The f o l l o w i n g equation was f i t t e d to the data- D = K, + K2 Vn + K3V + K4E + K5R + KÌ B + K 7 I where D i s the c r u s t a l thickness, i s the f i r s t l i n e a r regression c o e f f i c i e n t , Vn i s the upper man- t l e v e l o c i t y , V i s the mean c r u s t a l v e l o c i t y , E i s the e l e v a t i o n , R i s the regio n a l i s o s t a t i c anomaly (5° x 5° areas), B i s the Bouguer anomaly, and I i s the l o c a l i s o s t a - t i c anomaly (1° x 1° areas). The method i s f a r too crude to discover subtle r e l a t i o n s between v a r i a b l e s , but c e r t a i n consistent r e s u l t s permit some conclusions. (1) Of the above variables only the Bouguer anomalies and the mean c r u s t a l v e l o c i t i e s e x h i b i t strong l i n e a r r e l a t i o n s w i t h c r u s t a l thickness, (11) Considered alone i n simple regression analy- s i s , i s o s t a t i c anomalies and e l e v a t i o n also e x h i b i t s i g n i f i c a n t l i n e a r r e l a t i o n s w i t h c r u s t a l thickness, (111) I n no case i s the constant term s i g n i f i c a n t f o r g r a v i t y anoma- l i e s and e l e v a t i o n ; thus i t i s not proper to speak of 'standard c r u s t a l thickness' f o r zero anomaly or e l e v a t i o n , ( i v ) The data from the Soviet Union show consistent disagree- ment w i t h those obtained elsewhere i n the world. 5. Bibliography. a. Papers Presented at Meetings. R.P. Meyer, John Steinhart and G.P. Woollard: "Preliminary Results of Crustal Studies i n Mexico," Ann. Meeting Soc. Explor, Geophysicists, San Antonio, Tex., 1958. 671
INTERDISCIPLINARY RESEARCH R,P. Meyer, John Ste i n h a r t , CP. Woollard and W.E, Bonini: "Preliminary Re- s u l t s of Crust a l Studies i n Eastern Montana." F o r t y - f i r s t Ann. Meeting, AGU, Washington, D.C., A p r i l 1960. John Steinhart, G.P. Woollard: " S t a t i s t i c a l Uncertainty and I n t e r p r e t a t i o n Problems i n Seismic Crustal Studies w i t h A p p l i c a t i o n s , " F o r t y - f i r s t Ann. Meeting, AGU, Washington, D.C., A p r i l 1960. John Steinhart, G.P. Woollard- "Linear Analysis of the Results of Explosion Seismic Measurements on the Continents." Forty-second Ann. Meeting, AGU, Washington, D.C., A p r i l 1961. b. Published Papers. John Steinhart and R.P. Meyer "Explosion Studies of Continental Structure." Dept. of Terr. Magn., Carnegie I n s t , of Wash., Pub. No. 622, 1961. 409 pp. 672
INTERDISCIPLINARY RESEARCH Project 20.3 - Study of Marine Seismic Data 1. Objectives. I n the n o r t h and c e n t r a l P a c i f i c , seismic v e l o c i t i e s a t the surface of the sediments are about 1.5 km per second, while the average of the e n t i r e sediment layer i s 2.15 km per second. I f the v e l o c i t i e s increase l i n e a r l y , t h i s implies a marked v e l o c i t y gradient and a corresponding high degree of compaction near the base of the sediments. The question then arises whether the t r a n s i t i o n to the basement rocks represents a l i t h i f i c a t i o n process or whether these rocks have a very d i f f e r e n t character from the o v e r l y i n g sediments. This question can be studied by comparative measurements of the basement r e f l e c t i o n s a t d i f f e r e n t frequencies. With regard to the heat flow, a p a t t e r n seems to be emerging i n the measurements to date. This p a t t e r n i s r e l a t e d t o the bottom topography and may also be r e f l e c t e d i n the seismic r e s u l t s . Other questions regarding the bottom topography include thickness of the crust under the South American trenches, s t r u c t u r e of c o r a l a t o l l s and submerged guyots i n the Tuamotus, and the existence and nature of i s o s t a t i c e q u i l i b r i u m under regions of d i f f e r e n t average depth, f o r example the Albatross Plateau (East P a c i f i c Rise) and the surrounding basins. Analysis of Scripps I n s t i t u t i o n of Oceanography, U n i v e r s i t y of C a l i f o r n i a , San Diego, of seismic and heat flow r e s u l t s obtained on the I n s t i t u t i o n ' s ICY expedition to the southeast P a c i f i c were applied to the f o l l o w i n g studies a. The density, p o r o s i t y , and other properties of the t h i n (300+ m) layer of unconsolidated sediments. b. The nature of the t r a n s i t i o n between the unconsolidated sediments and the underlying 'basement' rocks having v e l o c i t i e s of about 5 km per second. c. The r e l a t i o n s h i p between heat flow through the sea f l o o r and the thickness and v e l o c i t y of d i f f e r e n t c r u s t a l layers and of the mantle. d. The r e l a t i o n s h i p between these thicknesses and v e l o c i t i e s and the ocean bottom topography. 2. Personnel. R.W. R a i t t was p r o j e c t d i r e c t o r ; senior s c i e n t i s t s associated w i t h these studies were H.W. Menard, G. Shor and R.P. von Herzen. 3. Results. The study of the East P a c i f i c Rise i s an example of the r e s u l t s of these analyses. From the ICY heat flow measurements, Menard and von Herzen found t h a t the East P a c i f i c Rise i s associated w i t h a r e l a t i v e l y narrow region of high heat flow f o r a t l e a s t 4000 km along i t s length (Figs. 2 and 3 ) . The r i s e i t s e l f i s a vast low bulge of the sea f l o o r comparable i n size to North and South America: 2000 to 4000 km wide and some 13,000 km long, w i t h an average r e l i e f of 2-3 km exclusive of l o c a l features such as volcanoes. The c r u s t of the r i s e i s o f f s e t m several places where i t i s i n t e r - sected by f r a c t u r e zones and the whole width of the r i s e has been displaced v e r t i c a l l y by several hundred meters along some f r a c t u r e zones. Shallow earthquakes are common along I t s c r e s t although i t has not been possible t o e s t a b l i s h whether the earthquakes are p r e c i s e l y aligned along the c r e s t . R a i t t and Shor found from analysis of the seismic work of the several Scripps IGY expeditions, and other work, th a t the r i s e i s matched by a very s i m i l a r feature m the mantle, which seems to have somewhat greater r e l i e f than the r i s e i t s e l f . Menard has postulated t h a t the r i s e extends under western North America (F i g . 2) and t h a t the down-sloping ocean bottom between C a l i f o r n i a and Hawaii i s the western f l a n k of the r i s e . However, the corresponding e l e v a t i o n of the mantle that i s found i n the oceanic regions has not been found under the c o n t i n e n t a l area of the r i s e . The e x p l o r a t i o n of the East P a c i f i c Rise and r e l a t e d geological and geophysical phenomena, along w i t h studies of other large topographic features of the oceans, has given r i s e to provocative t e c t o n i c t h e o r i e s , such as the mantle convection current proposed by B u l l a r d , Maxwell and Revelle ( F i g . 4 ) . 673
INTERDISCIPLINARY RESEARCH ⢠STATIONS CREST OF RISE < 1 « 10"*col c m - 2 s e c - ' > 3 > 10"*col cm-2 s e c " ' 4 Km CONTOUR Figure 2. Correspondence i n p o s i t i o n of the cre s t of the East P a c i f i c Rise and a pa t t e r n of heat flow. The points o f f the United States are based on unpublished observations by von Herzen. The band of high heat flow, l i k e the cre s t of the r i s e , appears to pass through the western United States. 674
INTERDISCIPLINARY RESEARCH AVERAGE FOR CONTINENTS AND OCEANS P A C I F I C AVERAGE DEPTK HICKNESSJ 3000 Km 2000 1000 CREST Figure 3. Crustal section and heat flow p r o f i l e s of the East P a c i f i c Rise. V e l o c i t i e s below the " c r u s t " are i n kilometers per second. The crust i s thinned under most of the r i s e , but the region of very high heat flow and anomalous "mantle" velo- c i t i e s i s confined to a narrow band on the c r e s t . PLAN OF ARCHED BUT UNDISPLACED BLOCK ⢠I 11 I t HASHETIC UMMAUES A^^TURE + - I \ PLAN OF ARCHED $ DISPLACED BLOCK j ^ ^ A T T ^ L A T T O M C O M P R E S S * ^ - r r T^fi 0 W "HEAT "TENSION r ^HIGH HEAT FLOW 1 Figure 4. A diagrammatic presentation of the convection- current hypothesis f o r the o r i g i n of various features asso- ci a t e d w i t h the East P a c i f i c Rise. 675
INTERDISCIPLINARY RESEARCH 4. BiblioRraphy. R.P. von Herzen- "Heat-Flow Values from the Southeastern P a c i f i c . " Nature, v o l . 183, March 28, 1959, pp. 882-3. H.W. Menard: "The East P a c i f i c Rise." Science, v o l . 132, no. 3441, Dec. 9, 1960, pp. 1737-46. H.W. Menard: "Consolidated Slabs on the Floor of the Eastern P a c i f i c . " Deep-Sea Research, v o l . 7, 1960, pp. 35-41. H.W. Menard- "Geology of the P a c i f i c Sea." Experientia, v o l . XV, 6, pp. 205-213. 676
INTERDISCIPLINARY RESEARCH Project 20.4 - Study of Long Period and Extensometer Data 1. Obiectives. This work a t the Seismological Laboratory, C a l i f o r n i a I n s t i t u t e of Technology, i n i t i a t e d a t h e o r e t i c a l and numerical analysis of data derived from the s t r a i n seismometers i n South America p e r t a i n i n g to a. Secular s t r a i n accumulation, to make t h e o r e t i c a l i n t e r p r e t a t i o n of the numeri- c a l data being provided and to search f o r c o r r e l a t i o n s w i t h s e i s m i c i t y , and earthquake s t r a i n release. b. Solid earth t i d a l s t r a i n s , observation of t i d a l s t r a i n s of the s o l i d e a r t h to provide the basis f o r computation of e l a s t i c and i n e l a s t i c parameters of the earth's i n t e r i o r . T h e o r e t i c a l methods must be found f o r discovering and removing e f f e c t s of the ocean tides and regi o n a l tectonic inhomogeneities. c. U l t r a - l o n g period seismic waves- t h e o r e t i c a l analysis of G waves, free o s c i l - l a t i o n s of the e a r t h , and long period body waves w i l l be made to y i e l d data on the i n e l a s t i c c h a r a c t e r i s t i c s of the deeper mantle, possible differences between the mantle under continents and oceans, and e l a s t i c and density contrasts between mantle and core. d. Possible s t r a i n s associated w i t h the free o s c i l l a t i o n s of the e a r t h , to study free o s c i l l a t i o n s of the e a r t h , separating by computational methods e f f e c t s of earth- quakes, harmonious components of e a r t h t i d e s , winds and ocean currents. The theory of these e f f e c t s must be extended to e x p l o i t the data f u l l y . 2. Operations. a. T i d a l s t r a i n s were calculated by numerical Fourier analysis of d i g i t i z e d s t r a i n records. Corrections due to ocean loading were applied and the Love number was com- puted. b. Tectonic s t r a i n s were separated from seasonal e f f e c t s by su b t r a c t i n g the two orthogonal components y i e l d i n g a f u n c t i o n p r o p o r t i o n a l to r o t a t i o n a l s t r a i n . This procedure eliminated a l l e f f e c t s due to surface loads on surface temperature d i s t r i b u - t i o n s . c. Free o s c i l l a t i o n s and long period wave analysis i s described i n p r o j e c t 11.14 of t h i s r e p o r t . 3. Personnel. Hugo Benioff and Frank Press were p r o j e c t d i r e c t o r s , another s c i e n t i s t associated w i t h t h i s p r o j e c t was Stewart Smith. 4. Results. The r e s u l t s are described m p r o j e c t 11.14 of t h i s r e p o r t . 5. Bibliography. a. Papers Presented a t Meetings. Stewart Smith and Francis Wu "Analysis of Earth Tide Strains." 1963 Annual Meeting, American Geophysical Union, Washington, D.C. b. Published papers are l i s t e d i n p r o j e c t 11.14 of t h i s r e p o r t . 677
INTERDISCIPLINARY RESEARCH Project 20.5 - A n a l y t i c a l Studies of Crust a l Structure 1. Objectives. S c i e n t i s t s a t the Seismological Laboratory, C a l i f o r n i a I n s t i t u t e of Technology, compared e x i s t i n g earthquake surface phase wave v e l o c i t y data w i t h explosion seismology r e s u l t s from the same region, and i n t e r p r e t e d the observed c o r r e l a t i o n be- tween Rayleigh wave phase v e l o c i t y , topography and Bouguer g r a v i t y anomaly. Advances i n methods of i n t e r p r e t a t i o n yielded much new information on c r u s t a l s t r u c t u r e from phase v e l o c i t y data which are now r e a d i l y a v a i l a b l e . 2. Operations. The phase v e l o c i t i e s of Rayleigh m the California-Nevada regions were determined using an array of three s t a t i o n s . The t h e o r e t i c a l dispersion waves f o r mult i l a y e r e d structures were computed by matrix formulation using d i g i t a l computers. The t r a v e l time and seismic r e f r a c t i o n data were obtained from recordings of both chemical and nuclear explosions. A s t r u c t u r e was chosen to be consistent w i t h the phase v e l o c i t y , t r a v e l time, and g r a v i t y data. I n the study of the shallow features of the crust (Mono Basin) only seismic r e - f r a c t i o n , g r a v i t y and magnetic data were u t i l i z e d . 3. Personnel. Frank Press was p r o j e c t d i r e c t o r . 4. Results. A three-phase analysis of c r u s t a l s t r u c t u r e m the California-Nevada border region was completed. Analysis of g r a v i t y data, surface wave v e l o c i t y data, and explosion seismology data were made to see i f a consistent p i c t u r e of c r u s t a l s t r u c t u r e could be obtained. I t has been demonstrated t h a t the three methods give con- s i s t e n t r e s u l t s only i f an intermediate c r u s t a l layer i s present. F i r s t a r r i v a l data from the explosion r e s u l t s show the presence of t h i s layer over a distance of some 150 km. The phase v e l o c i t y and g r a v i t y data were consistent w i t h the c r u s t a l thickness of approximately 40 km (the g r a v i t y anomaly was -100 mgals, Bouguer). The explosion seismology data i n d i c a t e a c r u s t a l thickness closer to 45 km. Had the intermediate layer been m i s i d e n t i f l e d , one might have concluded erroneously t h a t the crus t i s 30 km t h i c k or less i n t h i s region. By use of a l l three methods of e x p l o r a t i o n of c r u s t a l s t r u c t u r e . I t was possible to guard against erroneous i n t e r p r e t a t i o n s and to place more severe r e s t r i c t i o n s on c r u s t a l s t r u c t u r e than any single method can. More recent work o f f e r s the a l t e r n a t e suggestion t h a t the intermediate layer i s r e a l l y the mantle but w i t h a reduced seismic v e l o c i t y and density. This unique mantle m a t e r i a l may occur only i n orogenic regions. 5. Bibliography. Frank Press: "Some Implications on Mantle and Crustal Structures from G Waves and Love Waves." J. Geophys. Res.. 64. 1959, pp. 565-568. Frank Press: "Crustal Structure i n the California-Nevada Region." J. Geophys. Res.. 65, 1960, pp. 1039-1051. L.C. Pakiser, Frank Press, M.F. Kane: "Geophysical I n v e s t i g a t i o n of Mono Basin, C a l i f o r n i a . " B u l l . Geol. Soc. Am., 71. 1960, pp. 415-448. Frank Press "The Earth's Crust and Upper Mantle." Science, 133. 1961, pp. 1455- 1463. 678
INTERDISCIPLINARY RESEARCH Project 20.6 - Analysis of IGY A r c t i c , A n t a r c t i c , and P a c i f i c Records 1. Obiectives. Data obtained from seismograms c o l l e c t e d from IGY st a t i o n s operated by the U.S. Coast and Geodetic Survey, supplemented by data from other C&GS st a t i o n s and from IGY and other s t a t i o n s were analyzed. The f o l l o w i n g aspects were considered. a. Seismicity and l o c a t i o n of seismic areas i n A n t a r c t i c a and m the f a r Southern Hemisphere, and possible c o r r e l a t i o n s of a n t a r c t i c seismic patterns w i t h known b e l t s i n the South In d i a n , A t l a n t i c and P a c i f i c areas. b. I n t e r i o r e a r t h c o n s t i t u t i o n , sub-Pacific s t r u c t u r e , core phases. c. E f f e c t s of s h i f t i n g i c e , i f any, on s t a t i o n seismographs. d. Study of o r i g i n and transmission of microseisras during a n t a r c t i c records. 2. Operations. Telegraphic data from i n i t i a l i n t e r p r e t a t i o n s a t the s t a t i o n were received twice weekly f o r use w i t h other data i n l o c a t i n g earthquakes around the world. The o r i g i n a l seismograms were sent by a i r m a i l on a d a i l y schedule f o r f u r t h e r a n a l y s i s . The seismograms were a l l r e i n t e r p r e t e d and compared w i t h the data published by the Bureau Central I n t e r n a t i o n a l de Seismologie. Special e f f o r t was made to determine as many l o c a l earthquakes as possible i n each of the three regions. This included w r i t i n g f o r a d d i t i o n a l data from other observatories i n the area. The p e c u l i a r i t i e s of each s t a t i o n recording were noted i n c l u d i n g the frequencies and distances of l o c a l a c t i v i t y , the occurrence to T phases and deep character of some l o c a l earthquakes i n the South P a c i f i c and the long period character of some P phases observed i n the polar regions. These f i n a l i n t e r p r e t a t i o n s were published i n the Seismological B u l l e t i n s , IGY Supplements 119A through 216A. 3. Personnel. D.S. Carder and L.M. Murphy were p r o j e c t d i r e c t o r s ; John Hershberger and Robert Eppley were associated w i t h t h i s work. 4. Results. a, Microseismic Studies. P a c i f i c . Microseismic amplitudes and periods were measured from the records of Guam, Truk, and Koror f o r ten P a c i f i c typhoons. These data have been coordinated w i t h meteorological observations supplied by the U.S. Weather Bureau and U.S. Navy. A d d i t i o n a l microseismic data from a number of Japanese seismograph s t a t i o n s were also used to supplement the IGY s t a t i o n data. Preliminary r e s u l t s indicated no p o s i t i v e r e l a t i o n s h i p between microseisms and the changing storm i n t e n s i t i e s and storm distances from the recording s t a t i o n s . Lags between the time of closest approach of the storm and the time of maximum microseismic amplitudes were freque n t l y observed. This i s consistent w i t h previous studies of microseisms i n t h i s area. Evidence from the analysis of a number of storms suggests that microseismic propagation may be a f f e c t e d by c r u s t a l s t r u c t u r e , p a r t i c u l a r l y the Andesite l i n e separating the A s i a t i c and A u s t r a l i a n c o n t i n e n t a l areas from the P a c i f i c basin. Truk microseisms are s i g n i f i c a n t l y reduced when a storm passes over the v i c i n i t y of the Andesite l i n e . Further study w i l l be required to e s t a b l i s h a d e f i n i t e c o r r e l a t i o n . A n t a r c t i c ⢠Seven microseismic storms recorded a t Byrd Station and Amundsen-Scott (South Pole) were selected f o r a n a l y s i s . Records of these storms were requested from IGY s t a t i o n s a t Mirny, Mawson, Scott, H a l l e t t , and Halley Bay. Records have been r e - viewed from Mirny and Scott Base while Halley Bay reported no s u i t a b l e records a v a i l a b l e . b. Seismicity Studies. ( i ) A n t a r c t i c a : During the IGY, 67 earthquakes were located south of 50° South l a t i t u d e , a l l i n known seismic zones. 679
INTERDISCIPLINARY RESEARCH The only two earthquakes observed w i t h a re g i o n a l character were reported a t Byrd S t a t i o n on July 18 and September 4, 1957. The data obtained were i n s u f f i c i e n t f o r the c a l c u l a t i o n of r e l i a b l e epicenters, but the phase increments f o r both are i n agreement w i t h a l o c a t i o n i n the v i c i n i t y of Mt. Erebus, a region f o r which many very small shocks were recorded a t Scott Base. Two other earthquakes previously reported as possibly occurring i n the Ross Sea were proved to have d i s t a n t sources. I n general, the epicenters followed the submarine ridges but a v a i l a b l e charts of the region between 60° South, 20° West, and Bouvet Island and the region be- tween the Macquarie Rise and the southeast Indian Rise, d i d not show a topographic expression of t h e i r s e i s m i c i t y . The bathymetry i s not w e l l known and ridges may be found i n these areas. The trend of epicenters indicated by the data gathered during and since the IGY has a l t e r e d the patterns previously developed. P a r t i c u l a r l y , i t appears t h a t the trend of epicenters extends from the southern arm of the Scotia Arc across the South A t l a n t i c to the Indian Ocean and that the m i d - A t l a n t i c trend of epicenters i s truncated n o r t h of t h i s b e l t . The A n t a r c t i c Continent i s p r a c t i c a l l y aseismic, having fewer earthquakes than any other land mass. No a c t i v i t y was observed w i t h a possible association w i t h geologic s t r u c t u r e of Western A n t a r c t i c a even though the s e n s i t i v e s t a t i o n s of Byrd and South Pole were favorably located to record any a c t i v i t y i n t h i s region. No seismic connection p a r a l - l e l s the Indian extension i n t o A n t a r c t i c a , The s h i e l d p a r t of A n t a r c t i c a i s also aseismic as are other c o n t i n e n t a l s h i e l d areas. ( i i ) Guam. During the IGY, 1,026 earthquakes were recorded a t Guam. These were mostly l o c a l and reg i o n a l earthquakes a t a distance between 90 and 175 km from the s t a t i o n . V ariations were noted i n t h e i r appearance i n d i c a t i n g changes i n depth and geologic province. Several earthquakes, l o c a l a t Guam, produced T phases less than 80 seconds a f t e r the P phase a r r i v a l and had apparent v e l o c i t i e s less than 1.5 km/sec. ( i l l ) Truk- Only three l o c a l earthquakes were recorded, a l l i n the distance range of 80 to 150 km from the s t a t i o n . A t o t a l of 738 earthquakes were recorded, i n c l u d i n g many w i t h e x c e l l e n t T phases from the a c t i v e zone to the south. ( i v ) Koror A t o t a l of 905 earthquakes were recorded and only three were l o c a l i n character. Thus, there i s very l i t t l e evidence of any con t i n u a t i o n of the seismic zones of the Mariana Islands through Koror to New Guinea. (v) Thule, Greenland; A t o t a l of 567 earthquakes were recorded and 58 epicenters determined n o r t h of the A r c t i c C i r c l e , exclusive of ei g h t a r t i f i c i a l events i n Novaya Zemlya. Of these, 35 were located on the a r c t i c extension of the A t l a n t i c r i d g e , 12 i n northern Alaska, 5 I n the Soviet A r c t i c , 3 near the coast of Norway, and one each i n the Bering Sea, Yukon, and northeast of Greenland. No a c t i v i t y was recorded which ind i c a t e d a source on the Greenland land mass. c. P a c i f i c Basin Travel Times from Nuclear Explosions. Data from the P a c i f i c I s - lands IGY st a t i o n s were u t i l i z e d to evaluate P wave t r a v e l times from surface sources on B i k i n i and Eniwetok A t o l l s . Because of high raicroseismic background on Guam and Koror, only the l a r g e s t of the 1958 series of explosions were recorded. The depth of the Mohorovicic layer beneath the islands i s about 17 km and the speed m the top of the mantle i s 8.2 km/sec, which p e r s i s t s to distances of 18° (2,000 km). Speeds under the C o r d i l l e r a n region of North America are slower than t h i s and a r e g i o n a l shadow zone a t 1,100 km or so i s i n d i c a t e d . This shallow zone under the section of the P a c i f i c studied i s not so evident. 680
INTERDISCIPLINARY RESEARCH 5. Bibliography. a. Papers Presented a t Meetings. D.S, Carder- "PCP Travel Times from P a c i f i c and Other Sources." GSA Annual Meeting, 1963. Robert A. Eppley: "A Preliminary Report on An t a r c t i c a Microseisms." Eastern Section Seismological Society of America, 31st Annual Meeting, 1959. J.F. Lander. "Seismicity Around Guam and An t a r c t i c a During the IGY." Eastern Section Seismological Society of America, 31st Annual Meeting, 1959. J.F. Lander "Seismicity of A n t a r c t i c a . " Eastern Section Seismological Society of America, 34th Annual Meeting, 1962. b. Published Papers. D.S. Carder and L.F. Bailey- "Seismic Wave Travel Times from Nuclear Explo- sions." B u l l . Seismol. Soc. Am., vol.48, October 1958, pp. 377-398. D.S. Carder, D.W. Gordon, and J.N. Jordan "Surface Focus Travel Times." I n press. J.F. Lander. "Seismicity of A n t a r c t i c a and Guam." Earthquake Notes, v o l . XXX, M2, June 1959, p. 16. J.F. Lander. "Seismicity of A n t a r c t i c a . " M.S. Thesis, The American U n i v e r s i t y , Washington, D.C., 1962, 88 pp. 681
INTERDISCIPLINARY RESEARCH Project 20.7 - Analysis of IGY Land and Sea Gravity and Seismic Data 1. Objectives. Marine seismic r e f r a c t i o n data were i n t e r p r e t e d a t Lamont Geological Observatory f o r geological i m p l i c a t i o n i n l i g h t of g r a v i m e t r i c , magnetic and topographic data. Information was derived on the properties of sound transmission and of seismic waves through various media. Long period body and surface wave data and intermediate period body wave and higher mode surface wave ( i . e . , Lg waves) data from 13 s t a t i o n s were studied i n a broad program, in c l u d i n g determination of dispersion curves and c r u s t a l s t r u c t u r e , azimuthal properties of earthquakes as surface wave sources, geography of background noise, geography of fundamental and higher mode Love and Rayleigh waves, long-period microseisms, geography of Lg waves and e f f e c t s of f o c a l depth. 2. Operations. For marine seismic r e f r a c t i o n , see p r o j e c t 11.8. Seismograms from the s t a t i o n s of the cooperative network were examined i n d e t a i l f o r unusual features such as presence of higher modes, unusual d i s p e r s i o n , e t c . Analy- s i s of the s p e c i a l features was c a r r i e d out by determining the a r r i v a l times as a func- t i o n of frequency, by amplitude and phase measurements and by automatic a n a l y s i s . D i g i t a l computers were applied to seismological problems and t h e i r successful use gave r i s e to t h e i r large-scale a p p l i c a t i o n s of the present time. The f i r s t a p p l i c a t i o n s of analog data analysis i n t h i s f i e l d were made using a sound spectrograph f o r determining the v a r i a t i o n of frequency w i t h time automatically. 3. Personnel. Maurice Ewing was p r o j e c t d i r e c t o r ; senior s c i e n t i s t s associated w i t h t h i s work were J.L. Worzel, J.E. O l i v e r , W.C. Beckmann, C.L. Drake, G.H. Sutton, J. Nafe, and J. Ewing. 4. Results. For marine seismic r e f r a c t i o n , see p r o j e c t 11.8. The " s t a t e of the a r t " i n surface wave seismology up to the time of the IGY has been o u t l i n e d i n a paper by Ewing and Press, "Surface Waves and Guided Waves," Encyclopedia of Physics XLVII, Geophysics I , 1956. Detailed study i n s p e c i f i c cases of the surface wave t r a i n s f o r c o n t i n e n t a l paths revealed t h a t a large p o r t i o n of the seismogram corresponded to waves of higher modes of the Love and Rayleigh types. At the same time i t became apparent t h a t the Lg and Rg phases, a t least such phases recorded a t some distance from the source, could be i n t e r p r e t e d i n terms of normal mode propagation w i t h i n a r e l a t i v e l y simple model of the crust-mantle system. Once these higher mode waves were understood, they could be used f o r determination of c r u s t a l s t r u c t u r e and they provide very e f f e c t i v e l i m i t a t i o n s on a v a r i e t y of h y p o t h e t i c a l structures which may be used to e x p l a i n the surface wave d i s - persion i n a given case. At about the same time, measurement of Rayleigh wave phase v e l o c i t i e s were used f o r determination of c r u s t a l thickness f o r the f i r s t time, i n i t i a l l y i n l i m i t e d regions, and l a t e r f o r the e n t i r e United States. These measurements provide a more unique solu- t i o n to the c r u s t a l thickness problem and today they are i n large scale use. The a p p l i c a t i o n of high speed computers to the problem of normal mode propagation i n m u l t i - l a y e r e d media, both homogeneous and w i t h v e l o c i t y g radients, r e v o l u t i o n i z e d the use of surface wave data f o r determination of earth s t r u c t u r e . Data which pre- v i o u s l y were f i t approximately through the use of models of one or two layers can now be f i t as p r e c i s e l y as the data warrant, and the r e s o l v i n g power of the method thus markedly improved. Such procedures led to the confirmation, from surface wave data, of 682
INTERDISCIPLINARY RESEARCH the e x i s t e n c e of the low v e l o c i t y channel w i t h i n the upper mantle and to i t s d e l i n e a t i o n i n some d e t a i l beneath the c o n t i n e n t s and oceans. D i f f e r e n c e s i n the mantle beneath the continents and oceans were dis c o v e r e d . Other new means of data a n a l y s i s were devised. A sound spectrograph was a p p l i e d to the a n a l y s i s of earthquake s i g n a l s , w i t h s t r i k i n g r e s u l t s . Nuclear explosions generated s e i s m i c waves i n many c a s e s , and these sources were located much more p r e c i s e l y i n time and space than i s p o s s i b l e i n the case of n a t u r a l earthquakes. I n some c a s e s , waves were generated which are not commonly found when the source i s a n a t u r a l earthquake. Methods of a n a l y s i s of the d i s p e r s e d s u r f a c e wavetrain were developed which r e l a t e the motion a t the source to phase v e l o c i t y and the d i s p e r s i o n i n such a way t h a t i f two of these q u a n t i t i e s are known, the t h i r d may be obtained. Phase v e l o c i t i e s of mantle Ray l e i g h waves were determined i n t h i s way for the f i r s t time, and s e v e r a l s t u d i e s r e - l a t i n g the nature of s u r f a c e wave t r a i n s to the source were completed, c l e a r l y i n d i c a t i n g that t h i s method w i l l become, a t the very l e a s t , as important as the body wave method of such s t u d i e s . Long-period waves fo l l o w i n g P a t moderate e p i c e n t r a l d i s t a n c e s were c l e a r l y r e l a t e d to the n e a r - s u r f a c e wave guide and appear to correspond to l e a k i n g modes of t h i s guide. New instrumentation of much g r e a t e r s e n s i t i v i t y f o r the recording of long-period waves was developed. A v a r i e t y of a r e a s were explored for c r u s t a l s t r u c t u r e using data from the I n t e r - n a t i o n a l Geophysical Year network. The l a r g e s c a l e e f f o r t i n seismology a t the present time was i n s p i r e d to a l a r g e degree by the success of these IGY programs. The r e s u l t s l i s t e d above have been published i n numerous t e c h n i c a l j o u r n a l s as l i s t e d i n the b i b l i o - graphy f o l l o w i n g . 5. Bibliography. For marine s e i s m i c r e f r a c t i o n , see p r o j e c t 11.8. a. Papers based d i r e c t l y on data from the IGY LP and Lg programs and supported i n whole or i n p a r t by IGY funds. M. Ewing. "The C r u s t and Mantle of the E a r t h . " AGU Geophys. Mon. No. 2. NAS- NRC Pub. 590 (1958), pp. 186-189. J . O l i v e r - "Seismology and the IGY; Geophysics and the IGY." AGU Geophys. Mon. No. 2. NAS-NRC Pub. 590 (1958), pp. 190-197. R.L. Kovach: "Surface Wave D i s p e r s i o n f o r an A s i o - A f r i c a n and a E u r a s i a n Path." J . Geophys. Res., v o l . 64 (1959), pp. 805-813. J . O l i v e r : "Long Period Earthquake Waves." S c i e n t i f i c American, v o l . 200, no. 3 (March 1959), pp. 131-133. F. P r e s s , M. Ewing, and F. Lehner: "A Long-period Seismograph System." AGU Trans., v o l . 39 (1958), pp. 106-108. G. Sutton and J . O l i v e r : "Seismographs of High M a g n i f i c a t i o n a t Long Pe r i o d s . " Ann. Geophys.. v o l . 15 (1959), pp. 423-433. J . O l i v e r and M. Major: "Leaking Modes and the PL Phase." B u l l . Seism. Soc. Am., v o l . 50 (1960), pp. 165-180. 683
INTERDISCIPLINARY RESEARCH J. Brune "Radiation Pattern of Rayleigh Waves from the S.E. Alaska Earthquake of July 10, 1958." Pub. Dominion Observ.. v o l . XXIV, "A Symposium on Earthquake Mechanism," (1961), pp. 373-383. M. Landisman, Y. Sato, and M. Ewing: "The D i s t o r t i o n of Pulse-like Earthquake Signals by Seismographs." Geophys. Jour. Roy. Astron. Soc., v o l . 2 (1959), pp. 101-115. J. Dorman. "Numerical Solutions f o r Love Wave Dispersion on a Half-space w i t h Double Surface Layer." Geophysics, v o l . XXIV (1959), pp. 12-29. M. Ewing and F. Press: "Determination of C r u s t a l Structure from Phase V e l o c i t y of Rayleigh Waves, Part I I I . The United States." B u l l . Geol. Soc. Amer.. v o l . 70 (1959), pp. 229-244. Y. Sato: "Numerical I n t e g r a t i o n of the Equation of Motion f o r Surface Waves i n a Medium w i t h A r b i t r a r y V a r i a t i o n of M a t e r i a l Constants." B u l l . Seism. Soc. Am., v o l . 49 (1959), pp. 57-77. J. Oliver and M. Ewing- "Normal Modes of Continental Surface Waves." B u l l . Seism. Soc. Amer. , v o l . 48 (1958), pp. 33-49. J. Oliver and M. Ewing: "The E f f e c t of S u r f i c i a l Sedimentary Layers on Con- t i n e n t a l Surface Waves." B u l l . Seism. Soc. Amer., v o l . 48 (1958), pp. 339-354. Y. Sato: "Attenuation, Dispersion and the Wave Guide of the G Wave." B u l l . Seism. Soc. Amer., v o l . 48 (1958), pp. 231-251. J. Oliver and M. Ewing: "Higher Modes of Continental Rayleigh Waves." B u l l . Seism. Soc. Amer. , v o l . 47 (1957), pp. 187-204. M. Ewing, S. Mueller, M. Landisman, and Y. Sato "Transient Analysis of Earthquake and Explosion A r r i v a l s . " Geofis. Pura e Appl., v o l . 44 (1959), pp. 83-118. P.W. Pomeroy: "Seismic Waves from High-Altitude Nuclear Explosions." J. Geophys. Res., v o l . 65 (1960), pp. 3445-3457. Seismological B u l l e t i n s : P.W. Pomeroy, Hong Kong, 8 Aug. 1957 - 30 A p r i l 1958, Lamont Geological Observatory (1959). B.L. Isacks, Palisades, N.Y., 1 May 1958 - 31 Aug. 1958, Lamont Geological Observatory (1960). M. Major and R. Houtz, Suva, F i j i , 7 Dec. 1957 - 24 June 1958, Lamont Geological Observatory (1959). b. Papers based i n d i r e c t l y on the IGY LP and Lg programs and supported i n part by IGY funds. J. Dorman and D. Prentiss " P a r t i c l e Amplitude P r o f i l e s f o r Rayleigh Waves on a Heterogeneous Earth." J. Geophys. Res., v o l . 65 (1960), pp. 3805-3816. Y. Sato, M. Landisman and M. Ewmg, "Love Waves i n a Heterogeneous Spherical Earth, Part I . T h e o r e t i c a l Periods f o r the Fundamental and Higher Torsional Modes." J. Geophys. Res., v o l . 65 (1960), pp. 2395-2398. "Part 2. T h e o r e t i c a l Phase and Group V e l o c i t i e s . " J. Geophys. Res.. v o l . 65 (1960), pp. 2399-2404. 684
INTERDISCIPLINARY RESEARCH J. Brune, J.E. Nafe and J, Ol i v e r : "A S i m p l i f i e d Method f o r the Analysis and Synthesis of Dispersed Wave Trains." J. Geophys. Res., v o l . 65 (1960), pp. 287-304. J. Oliver and M. Ewmg. "Seismic Surface Waves a t Palisades from Explosions i n Nevada and the Marshall Islands." Proc. Nat. Acad. Sci., v o l . 44 (1958), pp. 780-785. J. Dorman, M. Ewmg, and J. O l i v e r : "Study of Shear V e l o c i t y D i s t r i b u t i o n i n the Upper Mantle by Mantle Rayleigh Waves." B u l l . Seism. Soc. Amer., v o l . 50 (1960), pp. 87-115. P. Pomeroy and G.H. Sutton- "The Use of Galvanometers as Band-rejection F i l t e r s i n Electromagnetic Seismographs." B u l l . Seism. Soc. Amer., v o l . 50 (1960), pp. 135-151. J.N. Brune and J. Ol i v e r "The Seismic Noise of the Earth's Surface." B u l l . Seism. Soc. Amer., v o l . 49 (1959), pp. 349-353. J. O l i v e r and J. Dorman: "The Second Shear Mode of Continental Rayleigh Waves." B u l l . Seism. Soc. Amer., v o l . 49 (1959), pp. 379-389. J.E. Nafe and J.N. Brune: "Observations of Phase V e l o c i t y f o r Rayleigh Waves i n the Period Range 100-400 Seconds." B u l l . Seism. Soc. Amer. , v o l . 50 (1960), pp. 427-439. Seismological B u l l e t i n s : R.B. Simon, Palisades, N.Y., 1 May 1957 - 31 Aug. 1957, Lamont Geological Observatory (1958). R.B. Simon, Palisades, N.Y., 1 Sept. 1957 - 31 Dec. 1957, Lamont Geological Observatory (1959). G. V. Latham, Palisades, N.Y., 1 Jan. 1958 - 30 A p r i l 1958, Lamont Geological Observatory (1959). H. M i l l e r , S.J., Palisades, N.Y., 1 May 1955 - 30 Aug. 1955, Lamont Geological Observatory ( I 9 6 0 ) . S. Su., S.J., Suva, F I J I , 25 June 1958 - 31 Dec. 1958, Lamont Geological Observatory (1960). R.B. Simon, Palisades, N.Y., 1 Sept. 1959 - 31 Dec. 1959, Lamont Geological Observatory (1960). 685
INTERDISCIPLINARY RESEARCH Project 21.1 - Analysis of CO2 Data 1. Objectives. This p r o j e c t a t the Scripps I n s t i t u t i o n of Oceanography was estab- l i s h e d to provide f o r a study of the data on carbon-dioxide concentration c o l l e c t e d under several p r o j e c t s . I t was hoped to e s t a b l i s h a value of the mean concentration of CO2 m well-mixed a i r and to t r y to study how CO2 i s mixed and d i s t r i b u t e d through the atmosphere. The e q u i l i b r i u m between CO2 i n a i r and sea water was also studied to determine the marine conditions e f f e c t i n g t h i s e q u i l i b r i u m and t o attempt to estimate the p o t e n t i a l capacity of the oceans to take up the CO2 being put i n t o the atmosphere. 2. Personnel. N.W. Rakestraw was p r o j e c t d i r e c t o r ; CD. Keeling was the p r i n c i p a l i n v e s t i g a t o r . 3. Results. From analysis of the ground c o l l e c t i o n s , sea sampling, and samples c o l - lected i n f l a s k s i n a i r c r a f t and measured l a t e r . Keeling, working m association w i t h Bert B o l i n , derived an o v e r - a l l p i c t u r e of the large-scale t r a n s f e r processes i n the troposphere. Figure 5 shows the y e a r l y averages of smoothed values. The d i s t r i b u t i o n suggests a net release of CO2 near the equator, compensated by absorption a t high l a t i t u d e s , plus a CO2 source a t 500mb a t northern m i d - l a t i t u d e s , which i s assumed to be the r e s u l t of release of CO2 from combustion of f o s s i l f u e l . The peak near the equator i s assumed to represent a n a t u r a l release of CO2 over the ocean surface. Re- s t r i c t i n g themselves to a rather simple model, the i n v e s t i g a t o r s suggest t h a t the land vegetation a t northern m i d - l a t i t u d e s i s responsible f o r a net CO2 consumption of about 1.5 X 10^3 kg during the vegetative period i n the summer and t h a t the n o r t h pole-equator exchange of CO2 amounts t o approximately 2 x 10^^ kg per year. They c a l c u l a t e an eddy d i f f u s i v i t y of 3 x 10 cm2/s f o r the o v e r - a l l h o r i z o n t a l mixing of the atmosphere on a gl o b a l scale. I t I S concluded that CO2 i s an e x c e l l e n t tracer element f o r studying c i r c u l a t i o n and mixing i n the troposphere and lower stratosphere and recommend th a t observation of CO2 continue during a few years a t two representative s t a t i o n s i n the Southern Hemi- sphere between l a t i t u d e s 20 and 60°S, th a t upper-air samples be taken a t a few levels i n n orth polar regions up to 10-12 km, and th a t north-south cross-sections be made a t least once or twice a month from northern m i d - l a t i t u d e s w e l l i n t o the Southern Hemi- sphere, preferably along two meridians 180° apart. 4. Bibliography. Bert B o l i n , CD. Keeling. "Large-scale Atmospheric Mixing as Deduced from the Seasonal and Meridional V a r i a t i o n s of Carbon Dioxide." JGR. v o l . 13, no. 13, July 1, 1963, pp. 3899-3920. J.C Pales, CD. Keeling- "The Concentration of Atmospheric Carbon Dioxide i n Hawaii." Submitted to JGR 1964. CW. Brown, CD. Keeling: "The Concentration of Atmospheric Carbon Dioxide i n An t a r c t i c a . " Submitted to JGR 1964. 686
INTERDISCIPLINARY RESEARCH 315 CO2 CONG (p-pm) 314 313 - ⢠CALCULATED ⢠o ASSUMED PT BARROW J . 700mb MAUNA LOA- ⢠SOUTH POLE 90 60 40 20 0 L A T I T U D E 20 5 0 0 mb 40 60 90 O N Figure 5. Annual average concentration of atmospheric CO2 as a f u n c t i o n of l a t i t u d e a t the surface, a t 700 mb, and a t 500 mb, shown by the symbols x, open square, and s o l i d square, r e s p e c t i v e l y . P l o t t e d points from 5° t o 85°S (shovm by open c i r c l e s ) are assumed values. 687
INTERDISCIPLINARY RESEARCH Project 21.2 - Theo r e t i c a l Study of Ozone Data 1. Objectives. This p r o j e c t was c a r r i e d out by the p r i n c i p a l i n v e s t i g a t o r as a guest worker a t the High A l c i t u d e Observatory, U n i v e r s i t y of Colorado, w i t h the o b j e c t i v e of obtaining a b e t t e r p i c t u r e of formation and de s t r u c t i o n of atmospheric ozone and of the v e r t i c a l and h o r i z o n t a l transport processes accounting f o r i t s d i s t r i b u t i o n . 2. Personnel. Hans U. Dlitsch was the p r i n c i p a l i n v e s t i g a t o r . 3. Results. This work was mainly concerned w i t h the measurements of v e r t i c a l ozone d i s t r i b u t i o n obtained i n almost 3-1/2 years of routi n e observations (January 1956 - A p r i l 1959) a t Arosa, Switzerland, using the so-called Umkehr method. These measure- ments were supplemented by the records of t o t a l amount obtained by the European network. Dutsch had shown that there i s a good c o r r e l a t i o n on day-to-day changes between Umkehr r e s u l t s and those obtained by Brewer's chemical sonde. However, the Umkehr evaluation gave a s l i g h t l y higher p o s i t i o n f o r the ozone maximum. Since then an e r r o r was discovered i n the secondary s c a t t e r i n g c o r r e c t i o n used m the evaluation of the Umkehr observations by comparison w i t h the r e s u l t s t h a t Sekera and Dave had obtained on m u l t i p l e s c a t t e r i n g e f f e c t s working along d i f f e r e n t l i n e s . The cor r e c t i o n s of the er r o r w i l l tend to b r i n g the ozone maximum down, and i t i s expected therefore t h a t s t i l l b e t t e r agreement w i t h the d i r e c t methods w i l l be reached. I t was, however, not possible to do the necessary computation to prove t h i s q u a n t i t a t i v e l y during the p r o j e c t period. The bulk of the Umkehr observations ( y i e l d i n g 700 determinations of v e r t i c a l ozone d i s t r i b u t i o n ) had been processed before t h i s work began. Another 500 Umkehr curves under conditions of cloudy sky were reduced a t Boulder. The evaluation was c a r r i e d out by e l e c t r o n i c computers through the courtesy of the U.S. Weather Bureau i n Washing- ton and the A i r Force Space Track Laboratory i n Bedford, Mass. As no very obvious c o r r e l a t i o n of ozone content a t d i f f e r e n t heights could be found w i t h large scale weather types as defined by the German Weather Service, i t was decided to compute c o r r e l a t i o n s between the ozone content a t d i f f e r e n t heights and various meteorological parameters i n the upper atmosphere and also between such ozone concentrations themselves. At the same time, running means on 3, 5, 9, and 15 days were computed. These c a l c u l a t i o n s were done on the IBM 709 Computer of the Western Data Processing a t UCLA. Some r e l a t i v e l y high c o r r e l a t i o n s e s p e c i a l l y w i t h temperature and tropopause height were found but w i t h a large month-to-month scatter showing the complexity of the processes involved. I t was concluded t h a t such s t a t i s t i c a l work had to be supplemented by more d e t a i l e d study of shorter periods i n v o l v i n g computation of v e r t i c a l motions and synoptical analysis. The sudden stratospheric warming th a t occurred m the second h a l f of January and ea r l y February 1958 was the most i n t e r e s t i n g case study. The ozone content i n the highest layers (30-50 km) showed an i n t e r e s t i n g long-term increase from 1956 through 1958, and the question can be raised whether t h i s r e f l e c t s a change of solar u l t r a - v i o l e t r a d i a t i o n as part of the solar cycle. Because these are only observations by one instrument the evidence i s not conclusive and should be supplemented by a longer period of observation using more than one instrument. Along w i t h the Umkehr observations, the t o t a l ozone amount a t n i g h t had been measured using the moon as a l i g h t source. These r e s u l t s were analysed a t Boulder. They show a s l i g h t decrease of ozone content from e a r l y to l a t e n i g h t , which i s thought to be due mainly to processes i n the heights between 50 and 90 km, where a secondary ozone layer may be temporarily formed a t n i g h t . These r e s u l t s were compared w i t h values computed from photochemical theory. 688
INTERDISCIPLINARY RESEARCH 4. Bibliography. H.U. Dutsch: "Auswirkungen des stratospharischen Umsturzes im Januar 1958 auf Ozonverteilung und Temperaturfeld uber Europa." Ver. Schweiz. Nat. Ges. im Kanton Aargau, I960, S. 90-91. H.U. Dutsch: "Ozone D i s t r i b u t i o n and Stratospheric Temperature F i e l d over Europe during the Sudden Wanning i n January/February 1958." Beitrage zur Physik der Atmosphare. 35, (1962), 87. A.W. Brewer, H.U. Dutsch, J.R. M i l f o r d , M. Migeotte, H.K. Paetzold, F. P i s c a l e r , E. Vigroux: " D i s t r i b u t i o n V e r t i c a l e de I'Ozone Atmospherique - Comparison de Diverses Methodes." Ann, de Geophys., v o l . 16, no. 2, A p r i l - June 1960. H.U. Dutsch: " M i t t e l w e r t e und we' t e r h a f t e Schwankungen des atmospharischen Ozongehalts i n verschiedenen Hohen liber Arosa." Arch. Met., Geoph.. B i o k l . . A, 13 (1962), 167. H.U. Dutsch: "Current Problems of the Photochemical Theory of Atmospheric Ozone." Proc. Symp. on Chem. Reactions m the Lower and Upper Atmosphere, San Francisco, 1961, published by Interscience, New York, 689
INTERDISCIPLINARY RESEARCH Project 21.3 - A n t a r c t i c Atmospheric-Oceanographic-Glaciologic I n t e r a c t i o n s 1. Objectives. This p r o j e c t a t the Weather Bureau, U.S. Department of Conmierce, was organized to undertake a broad study of r e l a t e d a n t a r c t i c data on the s t r u c t u r e and motions of the a n t a r c t i c atmosphere w i t h p a r t i c u l a r reference to the transport of heat and moisture and the ice budget. 2. Operations. Data from the U.S. a n t a r c t i c s t a t i o n s i n the form of punched cards and processed data were a v a i l a b l e through World Data Center A; copies of o r i g i n a l data from Mirny were a v a i l a b l e through the two U.S. meteorologists stationed a t Mirny during the IGY through a USSR-US cooperative arrangement. Data from other a n t a r c t i c s t a t i o n s were obtained from radio broadcasts, o r i g i n a l or processed data not being a v a i l a b l e i n most cases owing to the necessarily long delay i n forwarding a n t a r c t i c data to the IGY World Data Centers. Snow temperature and accumulation data were obtained from the various g l a c i o l o g i c a l p r o j e c t s and oceanographic data from reports of ship c r u i s e s , IGY World Data Center A and published data of cruises i n previous years, going back to the METEOR and DISCOVERY expeditions. 3. Personnel. H. Wexler was p r o j e c t d i r e c t o r , p r i n c i p a l s c i e n t i s t s associated w i t h t h i s work were M.J. Rubin, W.S. Weyant, K.J. Hanson, F. Ostapoff, E.G. Flowers, J.D. Kangos, and H.J. Viebrock. 4. Results. I n v e s t i g a t i o n s were c a r r i e d out along a number of l i n e s , a l l more or less r e l a t e d to the general i n t e r d i s c i p l i n a r y theme of the heat and water budget of Antarc- t i c a and surrounding regions. Following are b r i e f d e s c r iptions of work and summaries of r e s u l t s of some of the aspects of t h i s p r o j e c t : a. Analysis of Water Transports m the A n t a r c t i c Circumpolar Current. I n the Drake Passage, IGY data were used to determine the mass transport through the S t r a i t s i n d i f f e r e n t years and to determine possible v a r i a t i o n s i n the flow. A section along 20°E longitude (south of the Cape of Good Hope) was analyzed applying the same p r i n c i - ple as used i n the Drake Passage study. I n t h i s way, i t i s intended to a r r i v e at a complete water budget study of the A t l a n t i c Sector of the A n t a r c t i c Ocean. Within the framework of the heat and water budget studies i n A n t a r c t i c a , a re-exammation of the water budget i n the hydrosphere was undertaken m order to proceed from here more c o n f i d e n t l y to problems of the heat and water exchange between the d i f - f e r e n t oceans and a t the i n t e r f a c e between the ocean and the atmosphere. The analysis of a cross-section through the Drake Passage on the basis of a two-layered f l u i d sheet, f o r which evidence i s presented, leads to r e s u l t s q u i t e d i f f e r e n t from the heretofore accepted current s t r u c t u r e i n the Drake Passage as w e l l as i n the amounts of water c a r r i e d by these currents. The A n t a r c t i c Circumpolar Current was assumed to extend to the bottom by previous i n v e s t i g a t o r s ; thus, i n s p i t e of the moderate v e l o c i t i e s i n the upper layers, enormous amounts of water would c i r c u l a t e around the A n t a r c t i c continent. Sverdrup quotes approximately 110 x 10^ tons s e c " l , Kort even up to 190 x 10° tons sec"^. The r e s u l t s of the analysis are shown i n Figure 6, where two sections (some 250 miles apart) through the Drake Passage are presented d e p i c t i n g the geostrophic zonal flow f o r a l l depths. According to t h i s analysis only about 40 x 10^ tons sec"! are c a r r i e d to the east by the A n t a r c t i c Circumpolar Current, and a deep sea current below approximately 2000 m depth flows through the Drake Passage to the west, c a r r y i n g water of North A t l a n t i c o r i g i n i n t o the eastern South P a c i f i c ocean. The analysis of new data from the OB during the IGY shows th a t conditions i n the deep-sea c i r c u l a t i o n have not changed over a period of about 30 years. The trans- port m the A n t a r c t i c Circumpolar Current, however, increased by approximately 20% i n comparison w i t h the values from the DISCOVERY section of 1930. C u r r e n t l y , attempts are being made w i t h various current-measuring devices to provide o b s e r v a t i o n a l l y the basis f o r a b e t t e r understanding of t h i s important current system. 690
D I S C O V E R Y 382-387 OB 461 -468 62 61 60 S 9 98 3 7 S6°S-L«L D382 D383 D384 D385 D386 D387 ON V E L O C I T I E S In ^^/s H A T C H E D A R E A FLOW TO T H E WEST 62 61 60 S9 58 57 56 5 5 ° S Lat Figure 6. Oceanographic sections through the Drake Passage. M SO o M cn O M ITS t-> M 1 O EC
INTERDISCIPLINARY RESEARCH b. Temperature Changes on Day-to-Day and Monthly Mean Basis to Determine Relative Roles of Radiation. Advection and V e r t i c a l Motion, and to Derive Patterns of V e r t i c a l Motion and Horiz o n t a l Advection. Preliminary c a l c u l a t i o n s i n d i c a t e t h a t a secondary j e t appears during periods of r a p i d temperature change, a t l e a s t a t L i t t l e America, w i t h I t s axis j u s t below the tropopause and maximum speeds of 80 to 90 k t s . Maximum v e r t i c a l motions, on the order of 8 to 10 cm-sec"^, are associated w i t h these secondary j e t s . The maximum v e r t i c a l motions appear about 12 hours a f t e r the maximum winds a t the s t a t i o n and about 50 mb lower than the j e t a x i s . A day-to-day analysis of the f i e l d of temperature changes i n the atmosphere above L i t t l e America during June 1958 delineates some i n t e r e s t i n g r e l a t i o n s h i p s . The disappearance of the tropopause about June 22, apparently associated w i t h a surface cold f r o n t passage, i s accompanied by large temperature changes located a t the e r s t w h i l e tropopause l e v e l ( F i g . 7 ) . t o r the month as a whole, i n the upper tropospheric layer from 500 to 400 mb, the temperature changes were smaller than those i n the s t r a t o - sphere, averaging 0.1°C per day. The mean absolute values of the 24-hour temperature changes were 2.1°C i n the upper troposphere and 1.8°C m the stratosphere. Most of the d a i l y changes are the d i r e c t r e s u l t of advection w i t h only small compensating adiabatic changes, but the advective changes themselves on a monthly basis are nearly completely balanced by the adiabatic and r a d i a t i v e changes i n temperature. c. Sensible and Latent Heat Flux from the A n t a r c t i c Ocean to the Atmosphere. A study of evaporation and the t r a n s f e r of sensible heat f l u x from the A n t a r c t i c Ocean to the atmosphere i s q u i t e important as i t may shed l i g h t on processes i n f l u e n c i n g the general c i r c u l a t i o n . Data from several ships p a r t i c i p a t i n g i n the IGY program m A n t a r c t i c a were c o l l e c t e d . I t was intended to study the ocean surrounding A n t a r c t i c a as a whole, determining the heat f l u x f o r each 5° square f o r d i f f e r e n t seasons. Estimates have been made f o r the summer (December, January, February) and f a l l (March, A p r i l , May) seasons of the sensible and l a t e n t heat f l u x f o r 5° l a t i t u d i n a l zones from 40°S to 70°S eastward between 20°E and 180°. Results i n d i c a t e t h a t there are large v a r i a t i o n s i n the t o t a l heat f l u x from summer to f a l l and from zone to zone, the l a r g e s t seasonal v a r i a t i o n s occurring i n the zones 40''S to 45°S (183 c a l cm"2 day"l) and 65°S to 70°S (187 c a l cm-2 day-1). A minimum i n the t o t a l heat f l u x f o r both summer (16 c a l cm"2 day"l) and f a l l (-54 c a l cm"2 day"l) i s found i n the zone 50°S t o 55°S, the approximate mean p o s i t i o n of the A n t a r c t i c Convergence. Annml eva- poration values were determined revealing a minimum (15 cm) along the coast w i t h a secondary minimum (32 cm) m the zone 50°S-55°S. The study was extended to the A t l a n t i c sector (70°W to 20°E) f o r the summer season. Results show a minimum of t o t a l heat f l u x (-30 c a l cm"2 day"l) i n the zone 45°S to 50°S, the approximate mean p o s i t i o n of the A n t a r c t i c Convergence i n the At- l a n t i c sector. A study of the percentage frequency of fog revealed a maximum frequency (327.) of fog i n the zone 45° to 50°S. Annual evaporation values show a minimum (6 cm) i n the zone 70°S to 75°S, w i t h a secondary minimum (14 cm) i n the zone 45°S to 50°S. d. E f f e c t i v e Radiation. Temperature, pressure and wind data r e l a t i n g to surface temperature inversions have been extracted from the South Pole data, using a l t e r n a t e months during 1958. A case study was prepared showing loss of i n t e r n a l heat energy w i t h height from the surface to the 500-mb l e v e l f o r the World Meteorological I n t e r v a l of 15-24 June 1958. Computations of the i n t e r n a l heat energy loss a t the South Pole from the surface to the 400-mb l e v e l i n d i c a t e a maximum loss a t the surface and a secondary maximum at the top of the surface i n v e r s i o n . e. Airborne Solar Radiation and Albedo Measurements over the A r c t i c Pack-ice during the period 7 July to 19 August 1958, obtained from the U.S. Navy Hydrographic O f f i c e , were examined i n an attempt to determine albedo of sea-ice over large areas (Fig. 8 ) . Only measurements of r a d i a t i o n i n t e n s i t y under overcast sky were u t i l i z e d . 692
INTERDISCIPLINARY RESEARCH 100 " 1 \ 1 / I I I 400 +1 u 700 800 00 12 00 12 00 12 00 12 00 12 00 12 00 12 00 12 00 12 00 12 24 JUNE 21 22 23 24 25 26 27 28 29 30 GREENWICH DATE AND TIME Figure 7. Rate of change of m.v. temperature of 100 mb layer (°C/12-HR) L i t t l e America, June 21-30, 1958 Airborne Albedo Measurements ARCTIC OCEAN near Point Barrow Alaska JlB-r-XUGUST I95« Figure 8. Albedo of the A r c t i c Ocean f o r various amounts of i c e . 693
INTERDISCIPLINARY RESEARCH On a gross scale the albedo of the surface along 120°W from the North Pole to 74°N ranges from 40 to 52%. I f the average ice cover i s assumed to be 8.5 tenths and the puddle coverage three-tenths, the average albedo i s 46%. However, the standard d e v i a t i o n of the airborne determination i s 13%. Some discrepancies are noted between average albedo values from the study and previous assumptions. Results i n d i c a t e t h a t the a b l a t i o n of sea-ice i s greater than t h a t of s h e l f - i c e by a f a c t o r of 1.5, although t h i s connot be confirmed by past observations due to inhomogeneity of data. I n order to determine or v e r i f y the albedo values f o r the various c h a r a c t e r i s t i c ice surfaces a comprehensive surface and airborne albedo program i s required. An es- timate of the heat budget of the A r c t i c ice pack indicates a thermal energy gain a t the surface t o t a l i n g 5670 c a l cm"^ during the major melt month, Ju l y . As a r e s u l t the surface a b l a t i o n would t o t a l nearly 50 cm and about 2100 c a l cm"^ would be used f o r i n t e r n a l warming and melting of the i c e . f . Growth and Thermal Structure of the Byrd Land Ice. Instead of s t a r t i n g w i t h an i n i t i a l l y dry, below sea-level basin undergoing g l a c i e r i z a t i o n , as was done i n an e a r l i e r model, the present computations are based on the existence of an open channel connecting the Ross and Bellingshausen Seas. The period of g l a c i e r i z a t i o n begins as the sea m the channel freezes permanently and acquires accumulation, both from l o c a l p r e c i p i t a t i o n and transport from adjacent mountains. Times of growth of the ice s h e l f , by combined freezing from below and accumulation of 10 and 20 cm y r " l , r e s p e c t i v e l y , are determined f o r the case of a l i n e a r temperature p r o f i l e i n the i c e . A f t e r the ice shelf becomes grounded, f u r t h e r growth i s by accumulation only. Steady-state tempera- ture p r o f i l e s f o r ice sheets 2,300 and 4,300 m t h i c k are computed under assumption of constant geothermal heat f l u x of 10"^ c a l . cm."2 sec."l and compared w i t h observed temperatures i n the 300 m d r i l l hole a t Byrd S t a t i o n . With a geothermal heat f l u x of 10-6 c a l . cm.-2 s e c . - l , basal melting of the 4,300 m t h i c k ice i s found to e x i s t only f o r the smaller accumulation r a t e . The e f f e c t of down-slope motion and sin k i n g of ice s t r a t a on the v e r t i c a l tem- perature p r o f i l e of the surface layer i s studied w i t h the a i d of the Benfleld-Radok formula. Assuming no c l i m a t i c temperature change and an i n i t i a l temperature gradient at the ice cr e s t of 1°C increase per 100 m increase i n depth, the curve of best f i t of a l l those t r i e d i s f o r a sin k i n g r a t e of 20 cm y r " ^ and a down-slope speed of 85 m y r " ^ (2,130 y r . of motion from the ice c r e s t ) , g. Heating and Melting of F l o a t i n g Ice Shelves. Based on an observed temperature p r o f i l e through the Ross Ice Shelf a t L i t t l e America and p a r t i a l p r o f i l e s i n the Maud- heim Ice Shelf and the Filchner Ice Shelf near the E l l s w o r t h IGY s t a t i o n , various models of heating w i t h and without melting from below are analyzed to f i n d the residence time of the respective ice shelves over the ocean (Fig. 9 ) . Estimated movements are com- pared w i t h observed shelf movements seaward, 100 and 200 y r . melting rates f o r an ice shelf i n i t i a l l y 20,5°C below the freezing point of seawater are found as functions of the d e v i a t i o n of sea-water from i t s fr e e z i n g point and the eddy c o n d u c t i v i t y of the ocean below the ice s h e l f . Steady-state solutions based on constant accumulation and sink i n g i n an ice shelf of constant thickness are discussed. The e f f e c t of heating of an ice shelf from above and below as i t moves to a warmer atmospheric environment i s described and i t i s concluded t h a t the decreasing temperature w i t h depth observed only m the E l l s w o r t h ice i s a r e s u l t of i t s r a p i d motion from the h i g h l y colder region to the southeast of the s t a t i o n (Coats Land). h. Ice Budgets f o r A n t a r c t i c a and Changes i n Sea Level. Eight d i f f e r e n t ice budgets f o r the Antactic Ice Sheet were examined; f i v e c a l l f o r rates of increase of the ice (0,83 to 1.32 x 10^^ g y r " l ) and a concomitant decrease of sea l e v e l (2,3 to 3.7 mm yr"-'-). These values are i n r e l a t i v e l y good agreement, considering the wide dispersion of i n d i v i d u a l components of the budgets. The observed r i s e i n sea l e v e l . 594
INTERDISCIPLINARY RESEARCH U 300 ICE SHELF GROWTH FOR a =0, 10 and 20 cm yr-i YEARS Figure 9. Ice Shelf Growth f o r Various Accretion Rates. â¢20 8 C ⢠e toe RR /OS J F M A M J J A S O N O I I I I I I I I I I â¢s Figure 10. Comparison of Meteorological Parameters a t Mirny. 695
INTERDISCIPLINARY RESEARCH however, seems to c o n t r a d i c t the apparent increase of i c e . The thermal expansion of the oceanic column caused by " c l i m a t i c " warming of the oceans has been invoked to r e - solve the c o n t r a d i c t i o n . A 0.6 mm y r " l " r i s e " of sea l e v e l r e s u l t i n g from an observed 30-year warming i n t r o p i c a l A t l a n t i c Ocean water temperatures i s i n s u f f i c i e n t to o f f - set the drop m sea-level caused by the alleged increases of A n t a r c t i c i c e . I n view of the u n c e r t a i n t i e s of the various components of water exchange between ocean, atmosphere and land, and the lack of adequate data on long-period thermal changes a t a l l depths of the world's oceans, i t cannot be stated d e f i n i t e l y that the A n t a r c t i c Ice Sheet i s e i t h e r increasing or decreasing. 1 . Advection Across the A n t a r c t i c Boundary. For A n t a r c t i c a as a whole, i n June 1958 the 850-mb l e v e l had a pronounced e a s t e r l y c i r c u l a t i o n and outflow from the con- t i n e n t , probably due to the combined e f f e c t s of a b e l t of circumpolar low pressure n o r t h of the continent and the " a n t i - c y c l o n i c " topography of A n t a r c t i c a ; only i n the Ross Sea was t h i s p a t t e r n d i f f e r e n t . I n June 1958 the influence of the polar cyclone became evident a t 700 mb and a t a l l higher l e v e l s to 200 mb. The net mass-transport was outward from the continent i n June. I n December 1958 the net flow around the continent was e a s t e r l y a t 850, 700, and 500 mb - a t t h i s l a s t l e v e l due only to the a n t i - c y c l o n i c c i r c u l a t i o n over East A n t a r c t i c a - but the c i r c u l a t i o n was again cyclonic a t the higher levels and extended i n t o the stratosphere. The net meridional mass-transport i n December 1958 was from the n o r t h , w i t h the p r i n c i p a l c o n t r i b u t i o n from above the 650-irib l e v e l . I t i s f e l t t h a t an upper-level cyclonic c i r c u l a t i o n may e x i s t throughout the year w i t h v a r i a t i o n s only i n the i n t e n s i t y of the i n f l o w a t high l e v e l s , and outflow a t the low l e v e l s , plus summertime heating to account f o r the observed r i s e s i n the heights of the is o b a r i c surfaces. The Mirny data also give evidence of a cyclonic c i r c u l a t i o n a t higher l e v e l s over East A n t a r c t i c a during a l l months of the year, w i t h i n f l o w of mass a t the higher l e v e l s predominating, but some outflow a t the higher l e v e l s , p a r t i c u l a r l y i n January, February, and March 1958; the 850 and 700-mb levels show outflow almost e x c l u s i v e l y . A comparison of meridional mass-transport at Mirny w i t h cloudiness, temperature and p r e c i p i t a t i o n (Fig. 10) shows th a t surface meteorological conditions - p a r t i c u l a r l y when e f f e c t s of solar heating are s l i g h t - were st r o n g l y influenced by advection. A comparison of the 1957 and 1958 data a t Mirny i n d i c a t e that meridional advection and surface meteorological conditions vary g r e a t l y from month to month and from year to year. 5. Bibliography. A comprehensive bibliography i n c l u d i n g papers published by p r o j e c t personnel I S included w i t h p r o j e c t 8.2 - A n t a r c t i c Meteorological Program. 696
INTERDISCIPLINARY RESEARCH Project 21.4 - Polar Stratosphere Structure, C i r c u l a t i o n and Ozone D i s t r i b u t i o n 1. Objectives. This p r o j e c t a t the Weather Bureau, U.S. Department of Commerce, was devoted to the study of temperature changes and flow patterns i n the A n t a r c t i c s t r a t o - sphere, to r e l a t i n g these to s i m i l a r changes i n ozone and other atmospheric phenomena, and to comparison w i t h s i m i l a r data i n the A r c t i c . 2. Operations. Data from U.S. s t a t i o n s were a v a i l a b l e on punched cards or i n other reduced form, data from other s t a t i o n s were obtained e i t h e r through World Data Center A or, i n most cases, from radio broadcast of meteorological summaries. A r c t i c data were a v a i l a b l e from other IGY p r o j e c t s . As one of the e a r l y steps i n the ana l y s i s , a series of 50-mb maps was prepared. 3. Personnel. Harry Wexler was p r o j e c t d i r e c t o r ; other senior s c i e n t i s t s associated w i t h t h i s work were M.J. Rubin, W.S. Weyant, T . I . Gray, J r . , W.B. Moreland. 4. Results. a. E x t r a p o l a t i o n of 100-Mb Data to 50-Mb. Because of the paucity of 50-mb data during the winter a t a n t a r c t i c s t a t i o n s , the r e s u l t of lower b u r s t i n g heights of the radiosonde balloons, an equation was developed to enable computation of 50-mb heights from the 100-mb upper-air observations. I n the course of development, both a regres- sion equation r e l a t i n g the layer thickness to the 100-mb temperature and a simpler equation based on the assumption of a constant layer lapse-rate ( f o r a given l a t i t u d e and month) were tested on independent data. The average e r r o r i n the extrapolated 50-mb heights was only 10-15 geopotential meters from about 75°S to the Pole, and 20-25 gpm at higher l a t i t u d e s , w i t h l i t t l e d i f f e r e n c e i n the r e s u l t s obtained from the two forms of equation. Under the constant lapse-rate assumption, the basic equation used was H50 * "100 + 20,302 T i o o + 5486.4, w i t h these extrapolated values then corrected f o r month and l a t i t u d e . The c o r r e c t i o n curves f o r these two f a c t o r s ( F ig. 11) may also be regarded as graphs of the mean layer lapse-rate as a f u n c t i o n of month and l a t i t u d e . No bias of the observed 50-mb data towards higher or lower heights could be demonstrated. b. Stratospheric Temperature Changes. The autumn and winter cooling of the a n t a r c t i c stratosphere i s f a i r l y regular and apparently c o n t r o l l e d d i r e c t l y by the long-wave r a d i a t i v e f l u x . The r a t e of cooling a t 100 mb i s a f u n c t i o n of some power of the absolute temperature, w i t h a value of the exponent of temperature i n the range +3 to +5 g i v i n g a good f i t to the observed South Pole data. As noted by A l t , the spring warming f i r s t appears on the Indian Ocean side of the continent ( a t least f o r 1958), and gradually moves across the Pole. The winter cold core i s displaced away from i t s p o s i t i o n on the highland side of the geographic pole towards the Weddell Sea and Palmer Peninsula area, f i n a l l y moving o f f the c o n t i - nent completely to the western South A t l a n t i c Ocean. The warming observed a t the various s t a t i o n s m 1958 comes i n surges, usually w i t h strong cooling observed be- tween the surges. These temperature changes are due mainly to h o r i z o n t a l advection of temperature associated w i t h the j e t stream, only p a r t l y compensated by v e r t i c a l motions. Computations f o r L i t t l e America f o r October, 1958, showed that the mean abso- l u t e value of the 24-hour advective temperature change a t 200 mb was 5.4°C. The algebraic mean of the advective temperature change for the 350- to 50-mb layer of the 697
INTERDISCIPLINARY RESEARCH +20 +to G P M 0 - t o 90» 85" + 3 0 +20 +10 G P M - 1 0 - 2 0 A FO I LATITUI Sff" 75* 70* 65" LATITUDE E FO { DA kTE \ \ 15 1 15 1 15 1 15 1 15 I 15 APR MAY JUN J U L AUG SEP Figure 11. Corrections to H50 Value obtained from Nomogram. Figure 12. Monthly Mean Upper-Atmospheric Temperatures by 5° L a t i t u d i n a l Zones. 698
INTERDISCIPLINARY RESEARCH atmosphere was +1.8°C/24 hr., while the t o t a l change i n temperature was +0.4°C/24 hr. The f o l l o w i n g conclusions may be drawn about the October warming; the day-to-day and other short period warming i s l a r g e l y the d i r e c t r e s u l t of advection, w i t h adiabatic temperature changes of the same order of magnitude compensating f o r most, but not a l l , of the advective warming both on a short period and on a monthly basis. Every case of s u b s t a n t i a l advective temperature decrease during the month must be compensated by a nearly equal but opposite adiabatic change, since there i s presumably a net r a d i a t i o n a l heat loss i n a l l but possibly the topmost part of the layer. Not enough i s known about the v e r t i c a l d i s t r i b u t i o n of ozone i n the stratosphere to say c a t e g o r i c a l l y t h a t heating due to short-wave absorption does not overbalance the long-wave loss, but t h i s does not seem l i k e l y f o r a period as long as a month. The gradual warming of the cold center appears to be the r e s u l t of short-wave absorption by ozone i n the middle stratosphere, while advection erodes the edges of the cold pool as the core i s displaced as noted above. c. Stratospheric Advection Across the A n t a r c t i c Boundary. I n June 1958 the polar cyclone over A n t a r c t i c a which f i r s t became evident a t 700 mb extended i n t o the s t r a t o - sphere. I n December 1958 the stratospheric c i r c u l a t i o n up to the 100-mb l e v e l was also cyclonic. I t i s f e l t t hat the upper-level cyclonic c i r c u l a t i o n may e x i s t throughout the year, but w i t h some r i s e s i n the height of the isobaric surfaces due to summertime heating of the high l e v e l s . There i s also some evidence of an i n f l o w of mass at the high levels during a l l months of the year. The monthly mean temperature over and around A n t a r c t i c a was averaged by 5° latitude-zones from 50°S to the South Pole a t the 500-, 300-, 200-, 100-, and a t the 50-mb l e v e l s . I n winter (August) tropopause and stratosphere seem to have the usual m i d - l a t i t u d e features up to about l a t i t u d e 65°S. Poleward of there the tropopause becomes d i f f u s e and the mean temperatures show a steady decrease up to a t least the 50-mb level. As the values a t the higher l e v e l s are based on fewer observations, and because the winter ascents are prematurely terminated due to the very low temperatures, the mean temperatures are probably lower than shown. The strong l a t i t u d i n a l tempera- ture gradient of about 35°C a t the 50-mb l e v e l , and the 25°C gradient a t the 100-mb l e v e l , are probably even stronger, and are evidence of the strong polar n i g h t j e t a t the high l e v e l s . I n December there was less l o w e r - l a t i t u d e data a v a i l a b l e , but the high l a t i - tude s t a t i o n s show the pronounced tropopause and the strong heating i n the stratosphere t h a t are t y p i c a l of the summertime soundings. The temperature gradient i s weak, and a c t u a l l y reverses a t the 50-, 100-, and 200-mb lev e l s (Fig. 12). The wind f i e l d r e f l e c t s the above temperature a n a l y s i s , and we see t h a t i n winter the zonal wind component increases w i t h height a t a l l l e v e l s , while decreasing poleward of the c o n t i n e n t a l boundary; i n summer the zonal component increases up to the 200-mb l e v e l , and then f a l l s o f f sharply while s t i l l decreasing poleward, d. The Stratospheric Jet Stream. The circumpolar stratospheric j e t , m general, increases i n i n t e n s i t y from e a r l y f a l l through the winter to a maximum i n e a r l y s p r i n g , w i t h mean monthly zonal geostrophic wind speeds at 30 mb on the order of 200 knots or more i n l a t e September or e a r l y October. The j e t i s assymetric w i t h respect to the Pole, being located about 10° of l a t i t u d e f u r t h e r n o r t h on the A t l a n t i c Ocean side of A n t a r c t i c a than on the New Zea- land side. The j e t reaches i t s f u r t h e s t n o r t h p o s i t i o n i n e a r l y September, and then r e t r e a t s southward during October, f i n a l l y disappearing i n November as the s t r a t o - spheric warming destroys the meridional temperature gradient. The circumpolar j e t , during a period of r a p i d warming i n the Ross Sea area i n October 1958, appeared c o n s i s t e n t l y a t a lower l e v e l a t McMurdo Sound than at L i t t l e America; e i t h e r the j e t axis v a r i e d considerably m the v e r t i c a l or a core of maximum 699
INTERDISCIPLINARY RESEARCH winds (on the order of 200 k t . ) was qu i t e extensive w i t h a slope northward w i t h height. I n 1956 and 1957 none of the data ind i c a t e d winds of comparable magnitude a t e i t h e r s t a t i o n . I t cannot be determined i f no such strong j e t occurred during those years or i f the observations d i d not reach s u f f i c i e n t l y high l e v e l s a t the time of occurrence of the j e t . e. 50-Mb C i r c u l a t i o n During 1958. A series of 50-mb charts f o r 1958 was p l o t t e d and analyzed f o r ten-day i n t e r v a l s , and the c i r c u l a t i o n patterns revealed were compared w i t h those f o r 1957, as shown by Moreland's analyses. Both years e x h i b i t s i m i l a r patterns i n the f a l l and winter seasons but d i f f e r somewhat i n spring and summer. I n 1957, the polar vortex of winter began to weaken i n e a r l y October and by 21 November a closed anticyclone a t 50 mb encompassed the continent (Fig 13). The breakdown of the polar vortex, i n 1958, was more gradual and by the end of November the 50-mb c i r c u l a t i o n was characterized by an i r r e g u l a r p a t t e r n of closed cyclones and anticyclones ( F i g , 14) rather than a dominant anticyclone. 5, Bibliography. A comprehensive bibliography i n c l u d i n g papers published by p r o j e c t personnel i s included w i t h p r o j e c t 8.2 - A n t a r c t i c Meteorological Program. Figure 13. 50 mb. ch a r t , November 21, 1957. 700
INTERDISCIPLINARY RESEARCH Figure 14. 50 mb. c h a r t , November 27, 1958. 701
INTERDISCIPLINARY RESEARCH Project 21.5 - Analysis of IGY Oceanographic Data 1. Objectives. This p r o j e c t a t the Scripps I n s t i t u t i o n of Oceanography, U n i v e r s i t y of C a l i f o r n i a , San Diego, provided f o r the study of sea l e v e l , wave, and current data, as w e l l as marine geophysical data from observations a t land s t a t i o n s and from the oceanographic cruises i n the *Pacific during the IGY. 2. Personnel. R.R. Revelle was p r o j e c t d i r e c t o r ; E. Goldberg, John Knauss, June P a t t u l l o , Walter Munk, N. Rakestraw, Frank Snodgrass were the senior s c i e n t i s t s p a r t i - c i p a t i n g i n the analysis. (For analysis of seismic and heat-flow observation, see pr o j e c t 20.3.) 3. Results. a. Sea Level. Variations i n atmospheric pressure and s p e c i f i c volume a f f e c t sea l e v e l . Both of these f a c t o r s were found to vary considerably w i t h season. These two f a c t o r s , considered together, give the i s o s t a t i c p o r t i o n of the change i n sea l e v e l , t h a t i s , a change i n sea l e v e l t h a t does not involve a change i n mass of the t o t a l w ater-plus-air column. The no n i s o s t a t i c p o r t i o n of sea l e v e l change represents a change i n the t o t a l water-plus-air column above the sea f l o o r , and i s of considerable i n t e r e s t t o some problems i n geophysics, such as the perturbations i n the earth's r o t a t i o n . Sea l e v e l responds to changes i n atmospheric pressure somewhat as an Inverted barometer: sea l e v e l i s low when pressure i s high and vi c e versa; f o r each 1-mb change i n atmospheric pressure, sea l e v e l changes by about 1 cm. I n the P a c i f i c , seasonal changes i n atmospheric pressure are la r g e s t i n the n o r t h . F i g . 15 shows sea l e v e l - atmospheric pressure r e l a t i o n s h i p s f o r several l o c a t i o n s . At A t t u and Adak i t i s seen that there i s almost a complete m i r r o r r e l a t i o n s h i p , while f u r t h e r south, where the changes i n a i r pressure are not so great, the sea l e v e l does not m i r r o r as completely the changes i n pressure. The determination of change i n s p e c i f i c volume of water (usually important only i n the upper several hundred or so meters of the ocean) has shown th a t a t some lo c a t i o n s , sea l e v e l changes are almost e n t i r e l y due to changes i n s p e c i f i c volume. From F i g . 15 i t i s seen th a t the seasonal deviations i n s t e r i c l e v e l s are the la r g e s t i n low l a t i t u d e s and almost n e g l i g i b l y small a t high l a t i t u d e s . I t must be noted here t h a t observations of s p e c i f i c volume changes are not made a t exactly the same l o c a t i o n as sea l e v e l , as t i d e gauges are i n s t a l l e d i n near-shore locations and s t e r i c observa- t i o n s are made i n deeper water; t h e r e f o r e , there i s a c e r t a i n approximation inherent i n t h i s f i g u r e . The pressure and s t e r i c terms have been summed f o r a large number of P a c i f i c locations and the combined e f f e c t s , the i s o s t a t i c d e v i a t i o n , p l o t t e d f o r the P a c i f i c f o r the four seasons, centered on March, June, September, and December (see p u b l i c a t i o n l i s t e d i n Bibliography f o r d e t a i l s ) . The pressure and s t e r i c terms c o n t r i b u t e i n ap- proximately equal amounts, but usu a l l y not i n the same parts of the ocean. The pressure terms are more important i n high northern l a t i t u d e s , the s t e r i c i n the lower l a t i t u d e s . The t r a n s i s t i o n between these two c o n t r i b u t i o n s l i e s i n the region 40-45°N; i t was not possible to determine t h i s r e l a t i o n s h i p , i f i t e x i s t s a t a l l , i n the Southern Hemi- sphere owing to lack of s t e r i c data from regions f a r t h e r south than about 30-40°S. From the seasonal study i t was determined t h a t i n March and September, the sea l e v e l o s c i l l a t i o n i s p r i n c i p a l l y l a t i t u d i n a l , while i n June and December there i s an a d d i t i o n a l l o n g i t u d i n a l component. The general features of the March and September o s c i l l a t i o n are inverse to one another w i t h , moreover, approximately the same amplitude of departure from the zero l e v e l . I n June and December, while there i s a s i m i l a r change 702
INTERDISCIPLINARY RESEARCH JULY 1957 J4N 1958 I I I I I I I I I I I I I I I I I I ATTU r\ ADAK f-s KODIAK SITKA CRESCENT CITY SAN FRANCISCO 270H Figure 15. Sea l e v e l i n centimeters ( s o l i d l i n e s ) , nearby s t e r i c l e v e l s i n centimeters (dashed l i n e s ) , f o r selected t i d e s t a t i o n s . Values are monthly deviations from annual means, determined from data c o l l e c t e d during IGY, except a t Adak, where e a r l i e r s t e r i c data are used. 703
INTERDISCIPLINARY RESEARCH i n phase, the differences between these two periods are more pronounced than i n the e q u i n o c t i a l periods. Some of the features noted from t h i s analysis may probably be a s c r i b e d to inadequacies of data, and the use of some data t h a t are not t r u l y synoptic; some of the discrepancies found, however, between heights of sea l e v e l a c t u a l l y ob- served and the i s o s t a t i c o s c i l l a t i o n , are more probably due t o n o n i s o s t a t i c changes that are r e l a t e d , f o r example, to currents and wind s t r e s s . Some important l o c a l e f f e c t s were also found, f o r example, a d i f f e r e n c e of 3 cm from southeast to northwest along the main islands of Hawaii, L i s i t z i n ( v i s i t i n g s c i e n t i s t s a t Scripps) and P a t t u l l o suiranarize t h e i r analysis as f o l l o w s : "Over the open oceans as a whole the recorded seasonal departure i n sea l e v e l agree both i n sign and i n approximate magnitude w i t h the i s o s t a t i c departures computed from changes i n a i r pressure and i n water volume. We conclude t h a t the large-scale v a r i a t i o n s i n sea l e v e l are indeed i s o s t a t i c , t h a t i s , t h a t v a r i a t i o n s i n t o t a l means of a i r and water are small. Where barometric e f f e c t s are large , as they are n o r t h of 40°N, there must be appreciable seasonal v a r i a t i o n i n the mass of water present, of course, while i n low l a t i t u d e s only the water volume, not the water mass, varies appreciably. I s o s t a t i c conditions apparently do not p r e v a i l a t least along c e r t a i n parts of the c o n t i n e n t a l coasts. The China Sea, northern A u s t r a l i a , B r i t i s h Columbia, and Mexico south of Baja C a l i f o r n i a show the l a r g e s t discrepancies. I t i s a curious f a c t t h a t i n most cases, but not i n a l l , these discrepancies are of the same sign as the i s o s t a t i c term; t h a t i s , the seasonal v a r i a t i o n s seem augmented by the l o c a l c o a s t a l conditions. Large discrepancies f r e q u e n t l y appear around the t r o p i c a l i s l a n d s . Some of these have apparently been introduced by the comparison of an average i s o s t a t i c p a t t e r n w i t h recorded values c o l l e c t e d only during IGY. I n t h i s h i g h l y complex r e g i o n , small- scale e f f e c t s cannot be neglected, even i n the i s o s t a t i c term. I t may w e l l be, a l s o , th a t some of the recorded v a r i a t i o n s are not i s o s t a t i c , and an explanation must be sought elsewhere." b. Spectra of Long Period Waves and Relations to Various Kinds of Disturbances. Three wave recorders were placed on the bottom i n 100 meters of water two miles o f f shore from the exposed (western) s i d e o f S a n Clemente I s l a n d . F o r each of 90 days during 1959 three-hour records were taken and a complex cross-spectral matrix com- puted. I t i s believed t h a t t h i s represents the most extensive set of c a l c u l a t i o n s ever performed m an oceanographic experiment. On the basis of the d a i l y spectra the energy density was contoured on a f r e - quency-time diagram. This diagram shows very c l o s e l y the a r r i v a l of dispersive wave t r a i n s i n the form of sloping ridges. The in t e r c e p t s of these ridge l i n e s w i t h the frequency axis gives the time of the source. The slope of the l i n e s gives the d i s - tance. The height of the ridges i s an i n d i c a t i o n of the i n t e n s i t y of the storm system. I n a d d i t i o n , comparison between the recorders gives the wave d i r e c t i o n . The knowledge of time, distance, and d i r e c t i o n uniquely defines the source. Munk and his colleagues f i n d t h a t during the 90 days under consideration there were 30 well-defined sources. These being the summer months a l l but two of the sources came from the Southern Hemisphere. About one-third f a l l i n t o the region of the Ross Sea, more than h a l f l i e between New Zealand and An t a r c t i c a and three wave t r a i n s had t h e i r o r i g i n i n the Indian Ocean near the i s l a n d of Kerguelan. The l a t t e r have t r a - veled almost h a l f way around the earth before a r r i v i n g a t the wave recorders. Comparison w i t h southern hemisphere weather maps has been rather successful, i n d i c a t i n g that wherever adequate weather information was a v a i l a b l e some well-pronounced 704
INTERDISCIPLINARY RESEARCH and favorable meteorologic system had i n f a c t been observed. This defines now the source region of the southern sw e l l which plays such an a c t i v e r o l e i n modelling the beaches of C a l i f o r n i a , Hawaii, and many other areas. The two northern sources were associated w i t h very intense storms i n the Gulf of Alaska. They occurred i n October near the end of the experiment. Perhaps the most important r e s u l t of the study i s the development of a tech- nique f o r obtain i n g the d i r e c t i o n of a noise as a f u n c t i o n of frequency. I n the most general sense our r e s u l t s could be looked a t as a three-dimensional contour chart g i v i n g the dependence of energy density as a f u n c t i o n of frequency, time, and d i r e c t i o n . Subsidiary r e s u l t s include some estimates of the r e f l e c t i o n of wave energy by beaches as a f u n c t i o n of frequency and an i n d i c a t i o n that the very f l a t spectrum a t frequencies below t h a t of the swell i s i n f a c t due to nonlinear i n t e r a c t i o n w i t h the main sea and swe l l p a t t e r n . c. Analysis of Observations of Oceanic Currents. Two major currents were inves- t i g a t e d i n the P a c i f i c during the IGY- the Equato r i a l Undercurrent, now c a l l e d the Cromwell Current, and the E q u a t o r i a l Countercurrent. The d e t a i l e d oceanographic ob- servations, continued i n t o 1959 f o r the countercurrent, made i t possible to c a l c u l a t e t r a n s p o r t s , shear, v e r t i c a l and h o r i z o n t a l v e l o c i t y p r o f i l e s , and also t o determine v a r i a t i o n s i n these two great current systems. The Cromwell current i s a major feature of the c i r c u l a t i o n of the P a c i f i c ; i t s existence was unknown u n t i l 1951 when T. Cromwell, R.B. Montgomery, and E.D. Stroup of the U.S. Fish & W i l d l i f e Service made the f i r s t measurements of i t . The current was unpredicted by any theories of oceanic c i r c u l a t i o n . I t i s symmetrical about the equator and, as defined by the 25 cm/sec contour, i s a t h i n sheet, 300 km wide and 0.2 km t h i c k . At UO'W, the core of the current i s a t a depth of 100 m. V e l o c i t i e s of up to 150 cm/sec have been found, and the average t r a n s p o r t , based on four p r o f i l e s , estimated a t 39 x 10^ m^/sec. The current apparently ends near the Galapagos Islands at 92°W and has been traced w i t h c e r t a i n t y to 150°W. There i s evidence from Japanese work th a t the current extends to as f a r as 160°E. East-west p r o f i l e s of the c u r r e n t , a t 140°W, are shown i n F i g . 16. V e l o c i t y cross sections are shown i n F i g . 17. F i g . 18 shows a composite east-west p r o f i l e to a depth of 1000 meters; t h i s p r o f i l e shows th a t the east-flowing Cromwell current sheet i s bounded on top and bottom by westward-flowing water. During a fourteen day period, 32 observations were made a t 140°W on the equator; no evidence of s i g n i f i c a n t change i n v e l o c i t y s t r u c t u r e was evident from these observations. The peak v e l o c i t y v a r i e d between 120 and 150 cm/sec and the depth remained rather constant a t 100 t 12 m. The h i g h - v e l o c i t y core of the current i s not very t h i c k , w i t h large shears be- low and above. Changes of 150 cm/sec i n 70 m, or 2 x 10-2/sec were common. The v e l o c i t y gradient above the core i s u s u a l l y larger than t h a t below. Hydrographic observations were taken along w i t h the d i r e c t current observations i n the hope th a t some i n s i g h t could be found i n t o the nature and cause of the current. Through examination of the temperature s t r u c t u r e , and p r o f i l e s of oxygen, phosphate, and other c o n s t i t u e n t s , i t has been i n f e r r e d t h a t strong v e r t i c a l mixing a t the equator i s r e l a t e d to the Cromwell cur r e n t . A model has been worked out to show that mixing of two water layers a t the equator could produce h o r i z o n t a l pressure gradients. The pos- s i b i l i t y i s suggested t h a t the Cromwell current arises i n response to the pressure f i e l d produced by the wind-induced divergence a t the equator. (For d e t a i l s of these argu- ments, see a r t i c l e c i t e d i n bibliography below). This f i r s t d e t a i l e d i n v e s t i g a t i o n of the Cromwell current s t i l l leaves some matters to be i n v e s t i g a t e d ; f o r example, the existence, nature, and extent of the current east of 180°; the question of where does the water go i n the v i c i n i t y of the Galapagos; and the question of the t o t a l transport balance i n the e q u a t o r i a l P a c i f i c . 705
INTERDISCIPLINARY RESEARCH The P a c i f i c Equatorial Countercurrent flows eastward a few hundred miles north of the equator, separating the westward flowing North and South Equatorial Currents. I t i s r e l a t i v e l y narrow - 300-500 km wide and, as part of the wind-driven c i r c u l a t i o n , i s accounted f o r m the various theories of wind-driven oceanic c i r c u l a t i o n . The ob- servations i n 1958, however, established t h a t t h i s current transports f a r more water than had been estimated previously and i s a c t i v e t o a depth below the thermocline. Observations i n 1959 added t o the knowledge of the v a r i a b i l i t y of the current and showed th a t the v a r i a t i o n i n transport was remarkably l a r g e . I n 1958, transport was estimated at 60 x 10^ m3/sec while i n 1959 i t was found t o be only about 1 x 10^ m3/8ec, l a r g e l y r e s u l t i n g from great differences i n the deep flow. VThile the deep flow appeared to be i n approximate geostrophic e q u i l i b r i u m , there i s evidence of a superimposed cur- rent a r i s i n g from wind a c t i o n . The current shear was found t o be about h a l f t h a t i n the Cromwell cu r r e n t . Surface v e l o c i t y of the countercurrent was observed t o vary markedly from day t o day, and the t u r b u l e n t component was found to be comparable - up t o one-half or two-thirds of t h a t of the mean cu r r e n t . 4. Bibliography. Eugene L i s i t z i n , June P a t t u l l o : "The P r i n c i p a l Factors I n f l u e n c i n g the Seasonal O s c i l l a t i o n of Sea Level." J. Geophvs. Res., v o l . 66, no. 3, March 1961, pp. 845-52. J,G, P a t t u l l o : "The Seasonal V a r i a t i o n i n Sea Level i n the P a c i f i c Ocean During the I n t e r n a t i o n a l Geophysical Year 1957-1958," J. Marine Res., v o l . 18, no. 3, November 30, 1960, pp. 168-184. J.A, Knauss: "The Structure of the P a c i f i c Equatorial Countercurrent." J. Geophvs. Res., v o l . 66, no. 1, Jan. 1961, pp. 143-56. Edward B r i n t o n : "The D i s t r i b u t i o n of P a c i f i c Euphausiids." B u l l e t i n of the Scripps I n s t , of Oceanography, v o l . , No. , 1962. Robert L. Fisher, Robert M. N o r r i s : "Bathymetry and Geology of Sala y Gomez Southeast P a c i f i c . " B u l l e t i n of the Geological Society of America, v o l , 71, A p r i l 1960, pp. 497-502. Robert L. Fisher et a l : "Preliminary Report on Expedition DOWNWIND, IGY General Report. Series No. 2, June 26, 1958, National Academy of Sciences, National Research Council. Carl S. Hubbs: " I n i t i a l Discoveries of Fish Faunas on Seamounts and Offshore Banks i n the Eastern P a c i f i c . " P a c i f i c Science, v o l . X I I , Oct, 1959, pp. 311-316. Charles D. Keeling: "The Concentration and I s o t o p i c Abundances of Carbon Dioxide i n the Atmosphere." T e l l u s . v o l . X I I , 1960, pp. 200-203. Henry W. Menard: "The East P a c i f i c Rise," S c i e n t i f i c American, v o l . 205, no. 6, Dec. 1961, pp. 52-61. Henry W. Menard, C.J, Shipek: "Surface Concentration of Manganese Nodules." Nature, May-Oct, 25, 1958, v o l . 182, pp. 1155-1158, Reprinted i n Scripps I.O, Contributions, #967-1062, 1958, v o l . 28c,3. John L. Mero: "Minerals on the Ocean Floor." S c i e n t i f i c American, v o l , 203, no. 6, December 1960, pp. 64-72. Joseph L. Reid, J r . : "Evidence of a South Equatorial Countercurrent i n the P a c i f i c Ocean," Nature, v o l . 184, July 18, 1959, pp. 209-210. 706
INTERDISCIPLINARY RESEARCH Wil l i a m R. Riedel: "Oligocene and Lower Miocene Radiolaria i n T r o p i c a l P a c i f i c Sediments." Micropaleontology. v o l . 5, no. 3, July 1959, pp. 285-302. Carl J. Shipek- "Photographic Study of Some Deep-Sea Floor Environments i n the Eastern P a c i f i c . " B u l l e t i n of the Geological Society of America, v o l . 71, July 1960, pp. 1067-1074, 1 F i g . , 5 p i s . J.A. Knauss: "Measurements of the Cromwell Current." Deep Sea Research. Vol. 6, 1960, pp. 265-286. VELOCITY - cm/sec w 0 E -50 « 0 2»S H-42,27 APRIL H-41, 26 APRIL => 200 :) H-36, 23 APRIL H-38 24 APRIL lOO 200 300 Z'N H-39. 25 APRIL Figure 16. East-west current p r o f i l e s , made w i t h Roberts current meter a t 140° W 25-27 A p r i l , Section IV. 707
INTERDISCIPLINARY RESEARCH SECTION SS S9 H6 S4 SECTION II( SECTIONS! SZ9 S24 H3I S23 S22 0 SECTION Hftf SECTION IV H42 H4I H36 H38 H99 Figure 17. V e l o c i t y cross sections a t 140° W. Dots are observed p o i n t s , v e l o c i t y i s i n cm/sec; plus i s eastward and minus i s westward flow i n g current; s t a t i o n numbers are along the bottom. Section I (6-9 A p r i l ) : a l l but the equator s t a t i o n s were made by HUGH M. SMITH w i t h reference to deep parachute drogues. Section I I (12-18 A p r i l ) : a t l e a s t two sets o f measurements were made by HORIZON a t each anchored buoy. Section I I (a) i s drawn from data which give the l a r g e s t t r a n s p o r t ; Section I I (b) i s drawn from data which give the smallest t r a n s p o r t . Section I I I (20-22 A p r i l ) i s drawn from data obtained by HUGH M. SMITH. Section IV (23-27 A p r i l ) was made by HORIZON. The sta t i o n s are the same as those shown i n Figure 16. 708
-20 20 VELOCITY (cm/sec) 40 60 80 100 120 MO 200k 300k 400k 500K r CL i L l o 700k 800U 900U lOOOU nook Figure 18. A composite east-west v e l o c i t y current p r o f i l e , 0-100 m, a t the equator at 140° W, based on Roberts current meter and Swallow current f l o a t s . Uncertainty i n depth of Swallow f l o a t s i s indic a t e d by v e r t i c a l l i n e s . 709
INTERDISCIPLINARY RESEARCH Project 21.6 - Analysis of IGY Oceanographic Data 1. Objectives. This p r o j e c t a t the Un i v e r s i t y of Washington provided f o r the analysis and p u b l i c a t i o n of oceanographic data c o l l e c t e d by the oceanographic vessel BROWN BEAR during the IGY. Two extensive cruises were completed - the northern P a c i f i c and Gulf of Alaska, where many oceanographic s t a t i o n s of the CARNEGIE+ about 30 years e a r l i e r , were repeated. Observations include bathymetry, about 80 hydrographic s t a t i o n s , b i o - l o g i c a l hauls, sediment cores, large water samples, and d i r e c t current observations. 2. Personnel. R.H. Fleming was p r o j e c t d i r e c t o r ; R.C. Paquette, R.T. Gregory, Sayed E l Wardani were the p r i n c i p a l i n v e s t i g a t o r s . 3. Results. Improved d e s c r i p t i o n of the various current systems of the area r e s u l t e d from t h i s work. Carbon-14 analyses were c a r r i e d out to date water masses and to provide information on organic p r o d u c t i v i t y . The st a t i o n s were planned to provide, along w i t h s i m i l a r s t a t i o n s m more southerly areas undertaken by Scripps, a meridional p r o f i l e of the eastern P a c i f i c . The data from the two cruises of the BROWN BEAR were published as special reports (see Bi b l i o g r a p h y ) . 4. Bibliography. W i l l i a m Aron and Peter McCrery: "A Description of a New Species of Stomiatid from the North P a c i f i c Ocean." Copeia. no. 3, 1958, pp. 180-183. James A. Cast and Thomas G. Thompson. "Determination of the A l k a l i n i t y and Borate Concentration of Sea Water." A n a l y t i c a l Chemistry, v o l . 30, no. 9, 1958, pp. 1549-1551. W i l l i a m Aron: "Midwater Trawling,Studies i n the North P a c i f i c . " Limnology and Oceanography, v o l . 4, no. 4, 1959, pp. 409-418. Richard A, Barkley and Thomas G. Thompson: "Determination of Chemically Com- bined Iodine i n Sea Water by Amperometric and C a t a l y t i c Methods." A n a l y t i c a l Chemistry, v o l . 32, no. 2, 1960, pp. 154-158. Robert H. Gibbs and W i l l i a m Aron: "Astronesthes n i g r o i d e s , a New Species of Stomiatoid Fish from the Eastern P a c i f i c Ocean." Copeia, no. 2, 1960, pp. 134- 136. Richard A. Barkley and Thomas G. Thompson: "The T o t a l Iodine and lodate-iodine Content of Sea-water." Deep Sea Research, v o l . 7, no. 1, 1960, pp. 24-34. Sayed A. E l Wardani: " T o t a l and Organic Phosphorus i n Waters of the Bering Sea, Al e u t i a n Trench and Gulf of Alaska." Deep Sea Research, v o l . 7, 1960, pp. 201- 207. Maurice Rattray, J r . : " I n t e r p o l a t i o n Errors and Oceanographic Sampling." Deep Sea Research, v o l . 9, 1962, pp. 25-37. Maurice Rattray, J r . , Cuthbert M. Love and Diane E. Heggarty: " D i s t r i b u t i o n of Physical Properties Below the Level of Seasonal Influence i n the Eastern North P a c i f i c Ocean." Journal o f Geophysical Research, v o l . 67, no. 3, 1962, pp. 1099- 1107. W i l l i a m Aron: "The D i s t r i b u t i o n of Animals i n the Eastern North P a c i f i c and I t s Relationship to Physical and Chemical Conditions." Journal of Fisheries Research Board of Canada, v o l . 19, no. 2, 1962, pp. 271-314. 710
INTERDISCIPLINARY RESEARCH Y.R. Nayudu and Betty J. Enbysk: " B i o - l i t h o l o g y of Northeast P a c i f i c Surface \ Sediments." Marine Geology. I n press. Dean A. McManus: "Major Bathymetrlc Features Near the Coast of Oregon, Washing- ton, and Vancouver I s l a n d . " Northwest Science, v o l . 38, no. 3, 1964, pp. 65-82. Y.R. Najmdu: " B i o - l i t h o l o g y and Paleoclimatic Study of Northeast P a c i f i c Sediments." ( I n preparation - to be submitted to Marine Geology) W i l l i a m Aron: "Preliminary Report of Midwater Trawling Studies i n the North P a c i f i c Ocean, w i t h an Appendix: Descriptions of a New Species of Stomiatid and an U n i d e n t i f i e d Leptocephalus. by Wi l l i a m Aron and Peter McCrery." U n i v e r s i t y of Washington, Dept. of Oceanography Technical Report No. 58, Ref. 58-3, 1958. Wil l i a m Aron: "The D i s t r i b u t i o n of Animals i n the Eastern North P a c i f i c and I t s Relationship t o Physical and Chemical Conditions." Univ. of Washington, Technical Report No. 63, Ref. 60-55, Dept. of Oceanography, 1960. Richard H. Fleming and S t a f f : "Physical and Chemical Data, North P a c i f i c Ocean, BROWN BEAR Cruise 176, July-September 1957, f o r the I n t e r n a t i o n a l Geophysical Year of 1957-1958. Univ. of Washington, Dept. of Oceanography, Special Report No. 29, Ref. 58-22, 1958. Robert T. Gregory, Cuthbert M. Love, and Thomas 0. Martin: "An Integrated System f o r Automatic Processing of Oceanographic S t a t i o n Data." U n i v e r s i t y of Washington, Dept. of Oceanography, Special Report No. 33, Ref. M63-12. I n press. 711
INTERDISCIPLINARY RESEARCH Project 21.7 - Analysis of IGY Oceanographic Data 1. Objectives. This p r o j e c t i n the Department of Oceanography and Meteorology of the A g r i c u l t u r a l and Mechanical College of Texas was intended to analyze oceanographic data from the IGY cruise i n the Gulf of Mexico, Caribbean, and contiguous portions of the A t l a n t i c w i t h respect to the carbon dioxide concentration i n the a i r and the sea sur- face and to the carbon dioxide t r a n s f e r rates which could be measured from these data or supplemental laboratory data and, i n a d d i t i o n , to i n i t i a t e analysis of trace metal samples c o l l e c t e d on these cruises. 2. Personnel. Dale F. Leipper was pr o j e c t d i r e c t o r , D.W. Hood and Hugh McClellan were p r i n c i p a l i n v e s t i g a t o r s . 3. Results. a. Measurement of PCO? i n A i r and Water. The carbon dioxide data obtained during the IGY cruises included the preliminary cruise i n the Gulf of Mexico south of Galves- ton to Mexico and a r e t u r n leg 100 miles to the east, a cruise to Batabano Bay, Cuba, fo r i n v e s t i g a t i o n of the carbon dioxide system m shallow water over a completely c a l - careous calcium carbonate sediment, and the 5,000 mile cruise i n the Gulf of Mexico, Caribbean, and contiguous portions of the A t l a n t i c . During the above cruises a l k a l i n i t y and pH measurements were made i n d e t a i l a t a l l s t a t i o n s and the p a r t i a l pressure of carbon dioxide computed. I t was r e a l i z e d a t the outset t h a t the errors incurred i n t h i s system f o r obtain i n g p a r t i a l pressure of carbon dioxide i n the ocean are great because of the s e n s i t i v i t y of pH values i n the computations. Although every e f f o r t was made to measure pH to t .02 pH u n i t s or b e t t e r , e r r o r s even w i t h t h i s accuracy are about 30 ppm i n the p a r t i a l pressure of carbon dioxide and approximately represents the d i f f e r e n c e o f t e n found between PCO2 of a i r and atmosphere as determined by the d i r e c t measuring i n f r a r e d technique. Thus, the r e s u l t s were used to i n d i c a t e r e l a t i v e d i f f e r e n c e between the two independently measured values. Then too, measurement of PCO2 a t depth must s t i l l be done w i t h the system of pH and a l k a l i n i t y measurement and subsequent computation, because of samp- l i n g d i f f i c u l t i e s . Data on the PCO2 content of the surface water a t t y p i c a l s t a t i o n s i n the A t l a n t i c , Caribbean, and Gulf of Mexico are given Table I . TABLE I CO2 DATA FOR SURFACE OCEAN WATER Location Depth CI (m) %" pH C.A. Calculated meq/L. Buch Lyman (1932) (1956) CO2 Water (ppm) Measured A t l a n t i c 31°29'N, 60°52.5'W 20.00 22.97 8.10 2.61 452 489 297 Caribbean 21°54'N, 83''24'W 19.77 27.47 8.21 2.65 346 389 272 Gulf of Mexico 24°19'N, 2 20.00 28.89 8.15 2.64 426 460 293 83''34'W 10 19.98 28.87 8.27 2.66 300 330 290 712
5 0 0 4 0 0 Q. Q. O 3 0 0 2 0 X Measured CO2 In tha a i r ⢠Calculated CO2 (Buch) J I I L J L SoOO 1200 1400 1600 1800 2 0 0 0 2 2 0 0 2 4 0 0 0 2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 T I M E ( E S T ) Figure 19. Diurnal data obtained over calcareous deposits i n Batabano Bay, Cuba. A Three-necked reaction f l a s k D CÌ 'Ì Oj HeaaurLng Burette B Sea Water Saiq>ling Burette E Gas Geaeratlng Chaaber C Gas Sampling Burette F Source of sodlua hydroxide for gas absorption G Stroboscope Target MOTOR Figure 20. Schematic drawing of the apparatus used f o r COÌ t r a n s f e r studies. 713
INTERDISCIPLINARY RESEARCH (A8)«-(A8)t Figure 21. Semi-log p l o t of ( A s ) . f o r measurement of K f o r CO2 under simulated sea surface conditions. vs t 4 5 6 T I M E , H R S â 10 714
INTERDISCIPLINARY RESEARCH Diurnal data obtained over the calcareous deposits i n Batabano Bay are very dramatic as shown i n Figure 19. These data show a marked d i u r n a l cycle of PCO2, as measured by the d i r e c t CO2 method, but no such changes are observed f o r the computed values. These r e s u l t s , i f assumed to be r e a l , can only be explained by a n o n - e q u i l i - brium c o n d i t i o n between molecular CO2 and the other components of the CO2 system. The e q u i l i b r a t i o n method ( d i r e c t ) measured molecular CO2 independently of the r e s t of the CO2 system while the computation system assumes complete e q u i l i b r i u m has been established. The r e s u l t s of these experiments have prompted d e t a i l e d i n v e s t i g a t i o n of the system i n the laboratory. b. Invasion of CO2 i n t o Sea Water - Laboratory Study. This study was undertaken i n order to determine the e f f e c t of turbulence of the water on the t r a n s f e r rate of carbon dioxide through a simulated sea surface. Figure 20 shows a schematic of the apparatus used. I n Figure 21, the r a t e of CO2 invasion i s p l o t t e d against time f o r the various mixing rates u t i l i z e d i n the study. Figure 22 shows a summary of the data obtained i n which the r a t e of turbulence as measured by r e v o l u t i o n speed of the s t i r r e r i s p l o t t e d against the invasion constant. From these data i t i s clear t h a t turbulence of the sea surface i s of paramount importance i n determining the r a t e of carbon dioxide t r a n s f e r . Likewise, i n these experiments i t i s possible to extrapolate to zero s t i r r i n g speed and obtain a number f o r the t r a n s f e r rates through a s t a t i c sea surface without encountering the problems usual to working i n a s t a t i c system. The r e s u l t s from t h i s study are com- pared w i t h those obtained by others i n Table I I . The values obtained i n t h i s study are s i m i l a r t o those obtained by Bohr and are thought to represent a reasonable invasion rate constant f o r quiescent surfaces a t constant temperature and s a l i n i t y . I n t h i s study the a i r phase i s i n each case maintained homogeneous and exchange rates were de- termined under vigorous degrees of turbulence i n the water. From the data i t i s apparent that the r a t e of replacement of the surface water f i l m must be c o n t r o l l e d by the t u r - bulence of the water phase. I t thus f o l l o w s t h a t water turbulence i s a dominant f a c t o r i n determining the r a t e of t r a n s f e r of CO2 through the water i n t e r f a c e . Vigorous a g i - t a t i o n of the a i r phase simulating conditions of a storm would doubtless increase the rate of t r a n s f e r of CO2. This may be due to the concurrent increased turbulence of the water which point would be d i f f i c u l t t o evaluate. A t h e o r e t i c a l treatment of other i n v e s t i g a t o r s of exchange r a t e of CO2 i n the atmosphere and the sea supports the concept that water f i l m c o n t r o l s the t r a n s f e r r a t e . I t i s i n t e r e s t i n g to note that i f the average t r a n s f e r r a t e of 1.77 x 10"^ mg/cm^/min, as reported by Harmon Craig, which indicates a seven year residence time f o r CO2 i n the atmosphere, i s divided by the invasion c o e f f i c i e n t s reported i n Table I I , a value f o r p a r t i a l pressure f o r CO2 i n the atmosphere necessary to maintain the average t r a n s f e r r a t e i s obtained. For these data the p a r t i a l pressure necessary would range from 8,850 x 10"^ atmospheres to 55 x 10"^ atmospheres. Since the p a r t i a l pressure of CO2 i s approximately 315 ppm, the average exchange must be f a s t e r than that indicated i n the laboratory data as a r e s u l t of turbulence of the sea surface. c. Trace Metal Analysis. The analyses of samples c o l l e c t e d a t sea f o r trace metals were analyzed by c o l o r i m e t r i c techniques f o r Fe, Cu, and Zn by Dr. Yoshimi Morita, a v i s i t i n g s c i e n t i s t from Fisheries I n s t i t u t e , Tokyo, Japan. The analyses were completed on AEC Contract, under which work i s continuing on trace metals analyses by a c t i v a t i o n analysis techniques as w e l l as other appropriate physical and chemical methods. The trace metals samples were c o l l e c t e d i n seven-gallon, a l l polyethylene f a b r i c a t e d sample b o t t l e s designed to f i t on the standard hydrographic cast. The b o t t l e s used f o r storage were Pyrex glass spheres w i t h two side arms which were sealed i n the f i e l d w i t h a pro- pane to r c h . The glass storage b o t t l e s were pre-treated w i t h r e - d i s t i l l e d n i t r i c a c i d and f i n a l l y washed w i t h t r i - d i s t i l l e d water and sea water samples before c o l l e c t i o n of the samples. Usually twelve such samples were taken a t a single depth. When analysis was made the e n t i r e one l i t e r sample was used and the Pyrex b o t t l e completely washed to remove a l l absorbed or sedimented m a t e r i a l . The r e s u l t s obtained are given i n Table I I I . 715
INTERDISCIPLINARY RESEARCH I O s <? + > s M s d + s d �ooh 2 00 000 E«p8 - L . _ l _ 2DC 400 600 800 REVOLUTION SPEED, RPM 1,000 Figure 22. P l o t of K vs s t i r r e r speed v i n rev/min. TABLE I I RATE CONSTANTS FOR TRANSFER OF CO2 THROUGH THE SEA SURFACE Cm/Min" 1 MgCm2A tm" iMin" 1 K Invasion of CO2 a t Sea (Exp. 1) Invasion of CO2 a t Sea (Exp. 2) Evasion of CO2 At Sea Bohr (1899) Becker (1924) Mlyake & Hamada (1960) Guyer and Tobler (1934) This Study 0.96 0.50 0.78 0.121 0.017 0.011 3.6 0.168 1.76 0.91 1.36 0.26 0.033 0.020 6.6 0.32 0.062 0.025 0.065 0.007 716
INTERDISCIPLINARY RESEARCH TABLE I I I Concentration of Cu, Zn, and Fe i n the Ocean as Determined by Spectrophotometric Methods* (Dr. Y. Morita) S t a t i o n Data Sample Collected Depth (m) T o t a l Depth (fathoms) Cu g/L Zn g/L Fe g/l Gulf of Mexico 58-H-1-6. 23°55'N 94°30'W III- 2 8 - 5 8 200 3500 2120 0.4 0.5 1.0 0.4 5 7 58-H-1-16: 23°14'N 92°26'W IV-1-58 200 3500 2020 0.5 0.8 1.3 1.9 18 16 58-H-4-88. 25°23.5'N 85°01'W VI-26-58 125 500 3000 1820 0.5 0.7 0.6 0.6 1.4 0.9 8 8 7 Yucatan S t r a i t 48-H-4-9: 21°38.5'N 86°15'W V-17-58 100 1500 630 1.1 0.6 5.3 1.6 -- Mid North A t l a n t i c 58-H-4-41: 30°35.2'N 75°12.5'W V-29-58 100 409 2500 0.5 0.5 1.1 1.3 13 10 58-H-4-50 32°36.5'N 72°39'W VI-6-58 109 509 5005 2910 0.8 0.7 0.8 0.5 0.8 2.7 21 7 12 Mid North A t l a n t i c 58-H-4-60. 29°40'N 74°51.5'W VI-14-58 100 800 4000 2500 0.6 0.9 1.3 1.6 2.7 3.6 11 5 13 F l o r i d a Current 48-H-4-86: 23°40'N 82°52'W VI-25-58 100 500 900 1.6 1.0 3.8 3.3 13 7 Mid South A t l a n t i c 26°6.9'S 30°7.5'W X-3-58 150 1300 2735 0.8 1,1 1.4 7.1 6 13 21''27.5'W 37°7.0'W X-3-58 145 1380 2119 0.9 0.7 0.9 2.6 12 10 A n t a r c t i c ( P a c i f i c Basin) 56°38.6'S 66°17.0'W IV-6-58 93 930 930 1.2 1.1 5.2 9.9 58 64 Concepcion I s l a n d , Argentina 67''48'S 69°52'W III- 1 2 - 5 8 11-24-48 180 200 -- 1.4 0.9 0.9 0.4 22 21 *Analysis made w i t h Beckman DU Spectrophotometer. 717
INTERDISCIPLINARY RESEARCH Project 21.8 - Analysis of IGY Oceanographic Data 1. Objectives. This work at the Woods Hole Oceanographic I n s t i t u t i o n was p r i m a r i l y undertaken to c o l l e c t , analyze and pub l i s h the large mass of s t a t i o n s e r i a l data ac- cumulated by the I n s t i t u t i o n during and j u s t preceeding the IGY. The i n t e n t i o n was to provide a major reference work f o r the A t l a n t i c Ocean f o r study of long and short term features of the c i r c u l a t i o n . I n a d d i t i o n , phosphate data was analyzed and used i n c i r c u l a t i o n studies. Sedi- ments were to be analysed i n an attempt to study the t r a n s f e r of c e r t a i n elements between the ocean and bottom sediments. Isotope analyses were planned f o r studies of dates of paleoclimatic changes. B i o l o g i c a l samples from the oceans and sediments were also analysed. 2. Personnel. Dr. P.M. Fye was p r o j e c t d i r e c t o r , F.C. F u g l l s t e r supervised the pre- paration of the data a t l a s and C. O'D. I s e l l n , V.T. Bowen, R.G. Leahy, D.A. M c G l l l , and Bostwick Ketchum were other p r i n c i p a l s c i e n t i s t s associated w i t h various aspects of t h i s p r o j e c t . 3. Results. a. A t l a s of the A t l a n t i c Ocean. This volume contains the f o l l o w i n g data, p l o t t e d i n m u l t i c o l o r charts, or tabulated ( i ) T r a n s a t l a n t i c P r o f i l e s of Surface Layer Temperature a t 32°S, 24°S, 16°S, 8°S, 0°, 8°N, 16°N, 40°N. ( l i ) Temperature P r o f i l e s to Bottom at 32°S, 24°S, 16°S, 8°S, 0°, B'N, 16°N, 24''N, 28°N, 32''N, 36°N, 40°N, 43°N, 46°N, 48''N, 53°N, 58°N, 50°W, 66°W, and Caribbean Sea area. ( i l l ) S a l i n i t y P r o f i l e s to Bottom f o r same areas as f o r temperatures. ( i v ) S t a t i o n Data f o r 5 ATLANTIS Cruises, 1 CHAIN c r u i s e , 4 CRAWFORD cr u i s e s , 3 DISCOVERY cruises. (v) Bathythermograph Data f o r 1 ATLANTIS cruise and 4 CRAWFORD cruises. b. Phosphorus and Oxygen Data. Data from 24°S, S'N and 40''N have been subjected to dynamic analysis and calculated transports f o r t o t a l phosphorus, inorganic phosphate and dissolved oxygen'obtained. The data permit the estimation of the b i o l o g i c a l f a c t o r i n the equation of state f o r the non-conservative properties (oxygen and inorganic phosphate). I n t u r n , an examination of the AO-AP r a t i o i s possible which reconfirms the general estimate of the prop o r t i o n of organic constituents m the plankton blomass. P u b l i c a t i o n of the research included: ( i ) North south p r o f i l e s f o r the eastern and western basin, g i v i n g . Temperature S a l i n i t y Density T o t a l Phosphorus Inorganic Phosphate Dissolved Oxygen 718
INTERDISCIPLINARY RESEARCH ( i i ) F u l l p r o f i l e s f o r the three T r a n s a t l a n t i c s e c t i o n s , g i v i n g . S a l i n i t y D e n sity C a l c u l a t e d V e l o c i t y T o t a l Phosphorus Inorg a n i c Phosphate D i s s o l v e d Oxygen 4. Bibliography. F.C. F u g l i s t e r : " A t l a n t i c Ocean A t l a s . " Woods Hole Oceanographic I n s t i t u t i o n , A t l a s S e r i e s , v o l . 1, June 1960, Woods Hole, Mass. D.A. M c G i l l : "The D i s t r i b u t i o n of Phosphorus and Oxygen i n the A t l a n t i c Ocean, as Observed During the IGY 1957-58." Progress i n Oceanography, v o l . I I , Pergamon P r e s s , 1964. 719
INTERDISCIPLINARY RESEARCH P r o j e c t 21.9 - A n a l y s i s of Atmospheric and Oceanographic Data 1. O b j e c t i v e s . T h i s p r o j e c t of the Lamont G e o l o g i c a l Observatory, Columbia Univer- s i t y , provided f o r a n a l y s i s of s e v e r a l kinds of IGY data. I s l a n d observatory wave data ( t i d a l , long period, and g r a v i t y waves) and microbarograph data from s i x s t a t i o n s s t u d i e d i n r e l a t i o n to wave propagation, atmosphere/ocean coupling, and g l o b a l m i c r o - o s c i l l a t i o n s . Sea l e v e l records were studied i n r e l a t i o n to t i d e s , tsunami and s u r f a c e wave data and s e i s m o l o g i c a l and m e t e o r o l o g i c a l data to o b t a i n information on sea l e v e l changes from very s h o r t to as long a period as the d u r a t i o n of the observations allowed. A r c t i c data, i n c l u d i n g hydrographic, marine sediment core a n a l y s i s , topographic and c u r r e n t s were analyzed as a comprehensive r e g i o n a l g e o p h y s i c a l study of the A r c t i c a r e a . T h i r t y - t h r e e cores taken i n the A r c t i c , for example, have been of p a r t i c u l a r value i n developing new t h e o r i e s of g l a c i a l c l i m a t e c y c l e s and ocean c i r c u l a t i o n . C r u i s e data from two 10-month c r u i s e s , i n c l u d i n g deep sea cores and r a d i o - c h e m i c a l a n a l y s e s of water samples, deep sea photographs and chemical and gas a n a l y s e s / s e a water were analyzed i n terms of study of the g e n e r a l oceanic c i r c u l a t i o n . 2. Personnel. Maurice Ewing was the p r o j e c t d i r e c t o r ; s e n i o r Lamont s c i e n t i s t s a s - s o c i a t e d w i t h the work were: W i l l i a m Donn, Kenneth Hunkins, W i l l i a m Hapgood, W i l l i a m McGuinness, and C.T. F r a y . 3. R e s u l t s . A n a l y s i s of c a s e s of d i r e c t atmosphere-ocean coupling, such as t h a t of the Texas Tower which was destroyed i n a severe storm, showed simultaneous a i r and ocean records w i t h the same d i s p e r s i v e period c h a r a c t e r i s t i c s . Wave motion i n the a i r i n the v i c i n i t y of the Tower was shown to be t r a n s v e r s e to the c o a s t w i t h a v e l o c i t y equal to the t h e o r e t i c a l long-wave v e l o c i t y i n the water. The energy of the s u r f a c e p r e s s u r e p e r t u r b a t i o n , produced by wind shear i n the troposphere, was thus t r a n s f e r r e d w i t h resonant a m p l i f i c a t i o n to the sea s u r f a c e . Such d i r e c t coupling between the atmosphere and sea i s , however, somewhat r a r e i n connection w i t h severe storms. A frequent type of coupling I S that observed w i t h i n enclosed or p a r t i a l l y enclosed b a s i n s . Records from S t . George's Harbor, Bermuda, f o r example, o f t e n show s t r i k i n g coincidence between wave t r a i n s i n the t i d e records and the barograms. I n each c a s e , the d i r e c t i o n of water movement was c o r r e c t for the f i r s t motion on the baragraph, i . e . , an i n c r e a s e i n pressure produces a drop i n sea l e v e l . However, i n most c a s e s , the amplitude of the change i n sea l e v e l was g r e a t e r than the p r e d i c t e d e q u i l i b r i u m displacement, i n d i c a t i n g resonant a m p l i f i c a t i o n . I n the A t l a n t i c , sea l e v e l s t a t i o n s were e s t a b l i s h e d a t s e v e r a l l o c a t i o n s f o r IGY (see p r o j e c t 9.3), but the data was analysed i n d e t a i l only f o r Bermuda, which was the only l o c a t i o n where s e r i a l hydrographic observations were a v a i l a b l e , and I c e l a n d , be- cause i t was the northern-most s t a t i o n i n the m i d - A t l a n t i c . The I c e l a n d s t a t i o n showed a s l i g h t maximum i n the f a l l and a s l i g h t minimum i n the s p r i n g , t h i s annual r e s i d u a l v a r i a t i o n i s i n phase w i t h the annual temperature c y c l e and may be a t t r i b u t e d to the volumetric change i n the oceanic column; i t i s a l s o p o s s i b l e , however, t h a t i t may i n p a r t r e p r e s e n t the e f f e c t of water mass t r a n s f e r between continents and oceans. The high l a t i t u d e sea l e v e l r e s u l t s appear to correspond w e l l w i t h those obtained by Scripps workers for the P a c i f i c (see p r o j e c t 21,5). At Bermuda, a long s e r i e s of hydrographic observations made p o s s i b l e a d e t a i l e d a n a l y s i s of temperature, s a l i n i t y and d e n s i t y c r o s s s e c t i o n s , computations of the dy- namic depth anomalies to a depth of 2000 m and d e t a i l e d comparisons of these r e s u l t s w i t h the sea l e v e l data. Examination of the v a r i o u s data c l e a r l y i n d i c a t e d t h a t s t e r i c e f f e c t s are n e g l i g i b l e below 2000 m depth. The curve of r e s i d u a l s e a - l e v e l s e r i e s seems to^show no annual p e r i o d i c i t y but a s l i g h t i n d i c a t i o n of a f o u r - t o - f i v e month c y c l e ; no explanation of t h i s p o s s i b l e p e r i o d i c i t y i s forthcoming. Much of the apparent departure of the s e a - l e v e l curves beyond the l i m i t s of e r r o r i n the measurements seems to be random. 720
INTERDISCIPLINARY RESEARCH Seismic s t u d i e s c a r r i e d out from D r i f t i n g S t a t i o n Alpha, A r c t i c Ocean, r e v e a l e d d e t a i l s of a prominent submarine ridge which was named the Alpha R i s e . T h i s f e a t u r e trends a c r o s s the A r c t i c Ocean approximately p a r a l l e l to the Lomonosov Ridge, the minimum depth over the r i s e i s 1426 m, i n c r e a s i n g to over 3000 m to the north and south. Sub-bottom r e f l e c t i o n s r e v e a l e d a c h a r a c t e r i s t i c echo from a depth of s e v e r a l hundred meters below the ocean f l o o r i n the e a s t e r n p a r t of the r i s e , which has a rougher bottom texture than the western p a r t , where t h i s echo was not pronounced. An upper unconsolidated l a y e r was found to be 380 m t h i c k , but one p r o f i l e d i s c l o s e d a 2.80 km t h i c k l a y e r of 4.70 km/c v e l o c i t y , below which l a y the 'oceanic' l a y e r w i t h a v e l o c i t y of 6.44 km/s. Bottom t r a w l s i n the A r c t i c Ocean produced high percentages of g r a v e l , which proved to be predominantly sedimentary rocks w i t h few igneous of metamorphic specimens. One sandstone specimen was dated to be Permocarboniferous i n age. Bottom cores contained s i m i l a r pebbles a t sediment depths up to 115 cm, which were found to be t y p i c a l l y g l a c i a l m a t e r i a l which has undergone l i t t l e or no water t r a n s p o r t . I t i s concluded that these g r a v e l s have been r a f t e d by i c e from a shore c o n t a i n i n g a c t i v e g l a c i e r s , w i t h the probable sources deduced to be A x e l Heiberg I s l a n d , E l l e s m e r e I s - land, or the northern c o a s t of Greenland. Seismic s t u d i e s of sea i c e were c a r r i e d out during the IGY program. A n a l y s i s of r e s u l t s show that v e l o c i t i e s of l o n g i t u d i n a l and t r a n s v e r s e waves m i c e show a marked seasonal change which can be a t t r i b u t e d l a r g e l y to v a r i a t i o n s i n i c e temperature. With the a d d i t i o n of d e n s i t y data, the v e l o c i t y data made i t p o s s i b l e to c a l c u l a t e v a r i o u s e l a s t i c constants of sea i c e . F l e x u r a l wave d i s p e r s i o n was i n v e s t i g a t e d and the ex- perimental r e s u l t s were shown to agree w e l l w i t h theory, although i c e t h i c k n e s s , as determined from the d i s p e r s i o n of f l e x u r a l waves and a i r - c o u p l e d f l e x u r a l waves, i s u s u a l l y lower than t h a t determined d i r e c t l y , A continuous v e r t i c a l o s c i l l a t i o n of the A r c t i c Ocean i c e was monitored by s e i s - mometers and g r a v i t y meters i n the period range 15 to 60 s; displacement amplitudes were about 0.5 mm a t 30 s and they i n c r e a s e d roughly as the square of the period. These o s c i l l a t i o n s a r e , i n p a r t , generated by wind a c t i o n . I n one c a s e , i t was found that they were propagating waves. O s c i l l a t i o n s i n the period range 10 to 100 minutes were detected w i t h a t i d e recorder l o c a t e d on I c e I s l a n d T-3 w h i l e i t was grounded for a time 130 km NW of Point Barrow, A l a s k a . Displacement amplitudes were found to be about 1 cm a t 30 min. and were roughly p r o p o r t i o n a l to period. The A r c t i c Ocean wave s p e c t r a i s found to c o n t r a s t w i t h t h a t of other oceans; the s p e c t r a l peak due to sea and s w e l l i s absent and the measurements i n d i c a t e a monotonic i n c r e a s e i n displacement amplitudes as the periods range from about 0.1 to 60 s e c . i n deep water and from about 0.1 s e c . to 100 min. on the c o n t i n e n t a l s h e l f . Using the "core method" together w i t h geostrophic computations, a t e n t a t i v e i n t e r - p r e t a t i o n of the c i r c u l a t i o n of the deep water i n the Southwest I n d i a n Ocean was made by X.LePichon. A deep c u r r e n t towards the n o r t h having the c h a r a c t e r i s t i c s of a western boundary c u r r e n t was shown to be d e f l e c t e d and Wakened by the complex system of r i d g e s . The e x i s t e n c e of a homogeneous body of water e a s t of 60°E i s a t t r i b u t e d to the mixing of the A t l a n t i c deep water w i t h A n t a r c t i c waters, the s a l i n i t y being kept constant by a s m a l l inflow of deep water of North I n d i a n Ocean o r i g i n . There seems to be a good agreement between the core a n a l y s i s and the geostrophic i n t e r p r e t a t i o n . Both i n d i c a t e the e x i s t e n c e of a homogeneous and n e a r l y s t a t i o n a r y mass of deep water i n the Reunion B a s i n , except i n the Southwestern part where there i s a d e f i n i t e i n f l u e n c e of A t l a n t i c Deep Water, Both confirm the very important e f f e c t of the system of r i d g e s . The agreement on the Northward Deep Current i s c e r t a i n l y not c o n c l u s i v e . T h i s i n t e r p r e t a t i o n i s only probable. Such a flow of deep water towards the north was supposed by Stommel. T h i s "deep western boundary c u r r e n t " detected by the core method and suggested by the geostrophic i n t e r p r e t a t i o n has very p e c u l i a r f e a t u r e s . I t seems to be a much deeper c u r r e n t than the one flowing beneath the Gulf- Stream, the l a y e r of no motion having to be placed i n such a way that a d e f i n i t e c u r r e n t 721
INTERDISCIPLINARY RESEARCH appears towards the South i n the l a y e r of minimum oxygen, around 1500 meters. F u r t h e r - more, i t s flow i s d i s t u r b e d by a complex system of r i d g e s . The A t l a n t i c Deep Water goes north along the C o n t i n e n t a l Slope, then i s d e f l e c t e d from i t by the s m a l l r i d g e connected to the s h e l f along 35°E and i s f i n a l l y back to the south by the shallow . Mozambique Channel. There i s some evidence t h a t p a r t of t h i s water manages to pass a c r o s s the Madagascar Ridge, mainly immediately north of the Mid-Oceanic Ridge, having j o i n e d the upper p a r t of the eastward deep c u r r e n t . Once i n the Reunion B a s i n , i t seems to move slowly towards the north on the west s i d e . The complete j u n c t i o n of the Madagascar Ridge to the Mid-Oceanic Ridge would e x p l a i n the weakening of the c u r r e n t . Many questions are s t i l l unsolved, the most important being that of the e x i s t e n c e of important s e a s o n a l or annual changes i n the deep water c i r c u l a t i o n . A more homo- geneous network of s t a t i o n s , together w i t h a topographic survey of the Madagascar Ridge, would check what has been suggested here, e s p e c i a l l y i n the Agulhas B a s i n and i t s northern p a r t , t h i s being the key a r e a f or a b e t t e r understanding of the deep water c i r c u l a t i o n i n the In d i a n Ocean. 4. Bib l i o g r a p h y . W.L. Donn, W.T. McGuinness: " A i r Coupled Long Waves i n the Ocean." J . Met., v o l . 17, 515, 1960. W.L. Donn, W.T. McGuinness: "An I n v e s t i g a t i o n of Long Period Ocean Waves." Proc. Sym. on Tsunamis, Tenth P a c i f i c Science Congress, 1963. W.L. Donn, D. Shaw: "Sea L e v e l and Climate of the Past Century." S c i e n c e , v o l . 142, 1963, p. 1166. K. Hunkins: "Seismic Studies of the A r c t i c Ocean F l o o r . " Sc. Rep. No. 1, ARCRC-TN-60-257, October 1960. W. Swarzacker, K. Hunkins: "Dredged G r a v e l s from the C e n t r a l A r c t i c Ocean." Sc. Rep. No. 2. ARCRC-TN-60-258, October 1960. K. Hunkins: "Seismic Studies of Sea I c e . " JGR, v o l . 65, no. 10, October 1960, pp. 3459-72. K. Hunkins: "Waves on the A r c t i c Ocean." JGR, v o l . 67, no. 6, June 1962, pp. 2477-90. X. LePichon. "The Deep Water C i r c u l a t i o n i n the Southwest I n d i a n Ocean." Unpublished r e p o r t , Lamont G e o l o g i c a l Observatory, c a . 1961. 722
INTERDISCIPLINARY RESEARCH P r o j e c t 21.10 - P o l a r Vortex Studies 1. O b j e c t i v e s . T h i s work a t the I n s t i t u t e of Geophysics, U n i v e r s i t y of C a l i f o r n i a , Los Angeles, provided f o r the a n a l y s i s of a n t a r c t i c m e t e o r o l o g i c a l data i n order to study the behavior of the a n t a r c t i c c i r c u l a t i o n as compared w i t h that i n the a r c t i c , during times of l a r g e - s c a l e changes such as the breakdown of the polar vortex. The study included a t t e n t i o n to the f o l l o w i n g , the height of the vortex before breakdown; changes i n the same period i n the s t r a t o s p h e r e and ionosphere; s o l a r , magnetic and a u r o r a l phenomena t h a t are p o s s i b l y r e l a t e d to the vortex; d i s t r i b u t i o n and v a r i a t i o n of ozone, time r e l a t i o n s h i p s between changes i n the troposphere and s t r a t o s p h e r e ; p h y s i c a l c o nditions that determine the s t a b i l i t y of the polar vortex; t h e o r e t i c a l study of models. 2. Personnel. C.E. Palmer was p r o j e c t d i r e c t o r and p r i n c i p a l i n v e s t i g a t o r , and J.B. Gregory and R.C. T a y l o r were the p r i n c i p a l s c i e n t i s t s a s s o c i a t e d w i t h Dr. Palmer i n t h i s work. 3. R e s u l t s . There i s g e n e r a l agreement that the c i r c u l a t i o n of the winter-time polar s t r a t o s p h e r e , from about 20 km to about 50 km, i s dominated by an i n t e n s e cyclone cen- tered a t the geographic pole. The cyclone i s most h i g h l y developed a t the winter s o l s t i c e and a t t h i s time i s b a r o c l i n i c , that i s , the isothermal s u r f a c e s are about normal to the i s o b a r i c s u r f a c e s . The c o l l a p s e of the vortex i n s p r i n g has been i n v e s - t i g a t e d f o r the Northern Hemisphere and i s connected w i t h l a r g e - s c a l e phenomena such as 'explosive warmings.' The vortex changes r a p i d l y , accompanied by large temperature e f f e c t s , leading to the adoption of the term 'breakdown.' The e x p l a n a t i o n of the breakdown i s sought i n terms of a b a r o c l i n i c i n s t a b i l i t y t hat i s somehow a m p l i f i e d r a p i d l y and r e s u l t s i n the transformation of the c i r c u l a t i o n p a t t e r n . From synoptic a n a l y s e s of the 300-, 100-, and 50-mb s u r f a c e s , time s e c t i o n s a t the v a r i o u s a n t a r c t i c s t a t i o n s , d a i l y s y n o p t i c c r o s s s e c t i o n s along two meridians, and s t u d i e s of the d i r e c t i o n of v e r t i c a l motion through a n a l y s i s of the 300°, 400°, and 500°K i s e n t r o p i c s u r f a c e s on a few days, a model of the breakdown was constructed. The mean contours of the 50-mb l e v e l (see JGR, v o l . 65, no. 10) show the beginning of the breakdown on October 15, 1958, and i t s development through November 9, a t which time i t i s seen that the c i r c u l a t i o n over A n t a r c t i c a i s dominated by an e x t e n s i v e flow of a i r from the A t l a n t i c and I n d i a n Oceans toward the P a c i f i c . A f t e r t h i s time, the depression moved o f f the c o n t i n e n t northeastward and disappeared i n t o the South A t l a n t i c about November 15, a f t e r which a high became e s t a b l i s h e d over A n t a r c t i c a and the summer c i r c u l a t i o n was e s t a b l i s h e d . The simple model of the synoptic events, as g e n e r a l i z e d from the a n a l y s e s as w e l l as from the work of other i n v e s t i g a t o r s i s as f o l l o w s : a. The undisturbed v o r t e x extends from about 20 km to above 30 km, the zonal wind i n c r e a s i n g w i t h e l e v a t i o n i n t h i s range. The isothermal s u r f a c e s are approximately v e r t i c a l and c o n c e n t r i c w i t h the pole. The i n t e n s i t y of the vortex i n c r e a s e s through the polar night but, i n both hemispheres, no matter what time the breakdown occurs, the c i r c u l a t i o n appears to a t t a i n i t s maximum s t r e n g t h a t the winter s o l s t i c e . b. The disturbance leading to breakdown i s a long-wave p e r t u r b a t i o n , l a r g e l y h o r i - z o n t a l , of the zonal c u r r e n t c o n s t i t u t i n g the v o r t e x . The a m p l i f y i n g wave i s e i t h e r s i n g l e or double. There i s no evidence, as y e t , of a m p l i f i c a t i o n of a double wave system i n the Southern Hemisphere, but the number of ye a r s a v a i l a b l e for study i s too s m a l l to support any c o n c l u s i o n on t h i s p o i nt. c. V e r t i c a l motions accompany the breakdown and are l a r g e l y r e s p o n s i b l e f o r the temperature changes. 723
INTERDISCIPLINARY RESEARCH d. The disturbance f i n a l l y becomes very l a r g e , extending over a t l e a s t 50° l a t i - tude. I t then moves i n t o middle l a t i t u d e s . e. Events subsequent to the breakdown depend upon the season. I t the breakdown occurs i n winter or e a r l y s p r i n g , a new polar cyclone may form, of weaker i n t e n s i t y ; i f I t occurs i n l a t e s p r i n g , the a n t i c y c l o n e c h a r a c t e r i s t i c of the summer months g r a d u a l l y assumes c o n t r o l of the polar c i r c u l a t i o n . f . The a m p l i f y i n g disturbance i n the Southern Hemisphere appears to be almost s t a t i o n a r y . There i s as y e t no agreement concerning t h i s point w i t h r e s p e c t to the northern breakdown, some workers t r a c i n g the p e r t u r b a t i o n from e a s t to west, others from west to e a s t . I t i s p o s s i b l e t h a t d i f f e r e n t y e a r s d i f f e r i n t h i s r e s p e c t . At a l l events the migratory movement i s slow. A f u r t h e r a n a l y s i s of the i s e n t r o p i c s u r f a c e s (see b i b l i o g r a p h y below) over a longer period s u b s t a n t i a t e d the c o n c l u s i o n s summarized above. The a n t a r c t i c breakdowns so f a r known have a l l occurred a f t e r the v e r n a l equinox. The i n v e s t i g a t o r s emphasize, however, t h a t the transformation i s delayed for over one month a f t e r the sun has returned to the pole, and t h a t , when i t does occur, the s t r a t o - s p h e r i c temperature changes are of such magnitude and so r a p i d that they cannot be a t t r i b u t e d s o l e l y to the absorption of r a d i a t i o n by the warming a i r . An even more convincing argtment a g a i n s t the absorption hypothesis i s provided by the maps a l r e a d y d i s c u s s e d . For example, whil e warming takes place a t 50 mb i n e a s t A n t a r c t i c a between October 30 and November 4, c o o l i n g takes place between November 4 and November 9. N e v e r t h e l e s s , the a m p l i f i c a t i o n of the wave continues. I t i s not contended t h a t ab- s o r p t i o n of r a d i a t i o n may not, a t some l e v e l , i n i t i a t e the development, but i t seems probably t h a t , once i n i t i a t e d , the wave a m p l i f i e s as a r e s u l t of p r e - e x i s t i n g i n s t a - b i l i t y . Thus, i t would be unnecessary to p o s t u l a t e an e n t i r e l y d i f f e r e n t mechanism' fo r the breakdown of the north polar v o r t e x , which can occur i n the dark. The d i f - ference i n the behavior of the two cyclones could, on t h i s view, be the r e s u l t of t h e i r d i f f e r e n c e s i n s t a b i l i t y , e s t a b l i s h e d f o r whatever cause, during the polar n i g h t . Following t h i s hypothesis, one must conclude that the major temperature changes are due to convection i n the broad sense ( i n c l u d i n g a d v e c t i o n ) . Although the breakdown of the a r c t i c cyclone has been i n t e n s i v e l y s t u d i e d , the published a n a l y s e s r e f e r almost e x c l u s i v e l y to the Western Hemisphere. As f a r as they go, the maps show that the progress of the breakdown i n 1957 and 1958 and a l s o 1959 was s i m i l a r to t h a t described for A n t a r c t i c a , Scherhag's a n a l y s e s a t 25 mb of the whole northern hemisphere i n the s p r i n g of 1958, however, p a r t i c u l a r l y the maps f o r the period January 23-28, 1958 i n d i c a t e that the i n i t i a l a m p l i f i c a t i o n i s that of two waves, symmetrically placed w i t h r e s p e c t to the pole. I t i s c l e a r from the a v a i l a b l e evidence t h a t events i n the A l a s k a - E a s t S i b e r i a n r e g i o n i n the north correspond to those i n e a s t A n t a r c t i c a i n the south, whereas the Weddell Sea has i t s northern cognate i n Greenland. During northern breakdown, strong winds a c r o s s the pole have been observed or can be i n f e r r e d . At the end of January 1958, f o r example, north winds i n the neighborhood of lOOm/sec were reported a t 30 mb ovjer Thule f o r 4 days. A remarkable i n s t a n c e of c r o s s - p o l a r flow i n 1956 i s given by the passage of a cloud of v o l c a n i c dust from Kamchatka, a c r o s s the pole and on to the B r i t i s h I s l e s , c o i n c i d i n g e x a c t l y w i t h the period of breakdown. 4. B i b l i o g r a p h y . R.C. T a y l o r : "The Mean F i e l d s of Height, Temperature, and Wind Over S i x A n t a r c t i c S t a t i o n s , and Some I n f e r e n c e s . " Presented a t Am. Met. Conf, on S t r a t , Met., Minneapolis, August 1959. 724
INTERDISCIPLINARY RESEARCH J.R. B a l l i f - "A Note on the Paper by C.E. Palmer, 'The S t r a t o s p h e r i c Polar Vortex i n Winter'." JGR, 64, 2031, 1951. J.B. Gregory: "Radio Wave R e f l e c t i o n s from the Mesosphere:I. Heights of Occurrence." JGR, 66, 1961, pp. 429-445. R.C Taylor "Upper A i r Temperatures over Seven U.S. A n t a r c t i c S t a t i o n s : 1956-57." To be published by IGY World Data Center A C.E. Palmer and R.C. T a y l o r "The Vernal Breakdown of the S t r a t o s p h e r i c Cyclone over the South Pole." JGR, v o l . 69, no. 10, October 1960, pp. 3319-3329. R.C. Taylor "The Topography of the 400°K I s e n t r o p i c Surface Over A n t a r c t i c a Spring 1957." IGY Gen. Report No. 11, Nat. Acade. S c i e n c e s , Washington, D.C., 1960. C.E. Palmer and R.C. Taylor "The A n t a r c t i c S t r a t o s p h e r i c Vortex i n 1958." JGR, v o l . 64, no. 5, May 1961, p. 1591. R.C. T a y l o r : "Upper A i r Temperatures a t U.S. A n t a r c t i c S t a t i o n s 1956-57." IGY Gen. Report No. 14, Nat. Academ. Sc i e n c e s , Washington, D.C., 1961. 725
INTERDISCIPLINARY RESEARCH P r o j e c t 21.11 - A n a l y s i s of Blue G l a c i e r Micrometeorological Records 1. O b j e c t i v e s . The purpose of t h i s p r o j e c t was to analyze micrometeorological data which were c o l l e c t e d continuously for a period of 37 days under IGY Blue G l a c i e r P r o j e c t 4.3. A n a l y s i s work done included determination of s u r f a c e energy exchange and i t s components f o r eight-hour periods, independent e v a l u a t i o n of the long-wave r a d i a - t i o n balance a t the snow s u r f a c e , computation of t h e o r e t i c a l v a l u e s of water vapor ex- change for comparison w i t h v a l u e s a c t u a l l y measured, computation of t h e o r e t i c a l v a l u e s of heat t r a n s f e r from the a i r by eddy conduction, t e s t i n g of the methods f o r ,this com- putat i o n w i t h r e f e r e n c e to v a l u e s f o r eddy conduction determined a s the r e s i d u a l i n the equation of energy exchange, and i n v e s t i g a t i o n of mechanisms of suncup formation. I n a d d i t i o n to a n a l y s i s of the micrometeorological data, c e r t a i n other work w i t h the Blue G l a c i e r r e c o r d s , such as f u r t h e r c l i m a t o l o g i c a l s t u d i e s , was considered to be w i t h i n the scope of t h i s p r o j e c t . T h i s work included both study of the Blue G l a c i e r i n i t s e l f , and comparison w i t h weather and g l a c i e r records from other p a r t s of Washing- ton S t a t e , to see how w i d e l y the d e t a i l e d r e s u l t s from the Blue G l a c i e r work might be e x t r a p o l a t e d . 2. Personnel. P.E. Church was p r o j e c t d i r e c t o r for t h i s work, p r i n c i p a l s c i e n t i s t s were Edward LaChapelle and F . I . Badgeley. 3. R e s u l t s . The general period of g l a c i e r advance from about 1950 to 1955-57 i n the Northern Cascades of western Washington was present to a l e s s e r degree i n the Olympic Mts. I n the l a t t e r a r e a the only d e f i n i t e advance noted was t h a t of the B l a c k G l a c i e r on the northwest s i d e of Mt. Olympus, which reached a maximum i n 1958. The Blue G l a c i e r , which had been r e t r e a t i n g s i n c e f i r s t observed over 60 years ago, ceased to r e t r e a t i n 1955, and the terminus has s i n c e shown l i t t l e change. Most advances i n the Cascades had ended i n 1957, and the heavy a b l a t i o n summer of 1958 was marked by g e n e r a l r e - t r e a t i n g both here and i n the Olympics. T h e o r e t i c a l i n v e s t i g a t i o n s of s o l a r r a d i a t i o n d i f f u s i o n i n the s u r f a c e snow l a y e r s have led to expressions for energy d i s t r i b u t i o n w i t h depth, energy absorption a t a b l a c k undersurface, and the snow albedo. These c a l c u l a t i o n s i n d i c a t e t h a t the appro- ximate top 5-cm snow l a y e r p l a y s a s i g n i f i c a n t r o l e i n the snow albedo, and that ap- p r e c i a b l e r a d i a t i o n i s s c a t t e r e d back through the s u r f a c e from t h i s l a y e r . Experimental measurements under c o n t r o l l e d c o n d i t i o n s which did not r e q u i r e i n s e r t i o n o£ a sensing element i n the snow confirm v a l i d i t y of the t h e o r e t i c a l r e s u l t s . A i r temperature vapor pressure and wind v e l o c i t y p r o f i l e s near the snow s u r f a c e a t the Snowdome micrometeorological s i t e on the Blue G l a c i e r e x h i b i t frequent and marked anomalies. Wind v e l o c i t y maxima w i t h i n 1 to 2 meters of the snow s u r f a c e a r e commonly caused by shallow drainage winds i n f a i r weather. D i f f i c u l t i e s i n instrumentation render d i f f i c u l t the i n t e r p r e t a t i o n of o f t e n e r r a t i c vapor pressure p r o f i l e s . The a i r temperature p r o f i l e s many times e x h i b i t e d a maximum w i t h i n 1 to 2 meters of the snow s u r f a c e , suggesting an apparent heat source a t t h i s l e v e l f o r which no e x p l a n a t i o n i s a v a i l a b l e . These temperature anomalies have been i n v e s t i g a t e d a t length i n the f i e l d , and are shown to occur only on sunny days and under c o n d i t i o n s of l i g h t p r e v a i l i n g winds. They d i d not occur a t n i g h t , i n cloudy weather, during high winds, or when drainage winds were blowing. Attempts to c a l c u l a t e convective heat and vapor exchange a t the snow s u r f a c e from these p r o f i l e s l a r g e l y met w i t h f a i l u r e due to the many i r r e g u - l a r i t i e s . I t I S concluded t h a t the e r r a t i c mountain a i r c u r r e n t s over a s m a l l , a l p i n e g l a c i e r such as the Blue G l a c i e r make the v a l u e of p r o f i l e o b servations f o r energy exchange c a l c u l a t i o n s r a t h e r dubious, and that s u r f a c e energy exchange elements a r e best obtained by the energy balance method i n these circumstances. 726
INTERDISCIPLINARY RESEARCH 4, Bibliography, E, LaChapelle: "Recent G l a c i e r V a r i a t i o n s i n Western Washington." a t the F o r t y - f i r s t Ann. Meeting, AGU, A p r i l 1960, Washington, D.C. Presented E. LaChapelle: "Energy Exchange Measurements on the Blue G l a c i e r . " Presented a t the X l l t h G eneral Ass., lUGG, H e l s i n k i , F i n l a n d , August 1960; publ. m Pub. No. 54 of the lASH Snow and I c e Commission, pp. 302-311; c o n t r i b u t i o n no. 57 Dept. of Met, and C l i m a t , , Univ, Washington, J.C, Giddings, E. LaChapelle: " D i f f u s i o n Theory Applied to Radient Energy D i s t r i b u t i o n and Albedo of Snow." JGR, v o l . 66, no, 1, Jan, 1961, pp. 181-9. 727
INTERDISCIPLINARY RESEARCH P r o j e c t 21,12 - A n t a r c t i c I c e Accumulation Study 1. O b j e c t i v e s . T h i s p r o j e c t a t the I n s t i t u t e of Polar S t u d i e s , Ohio State U n i v e r s i t y , provided for the a n a l y s i s of snow p i t and rammsonde data taken during the IGY i n Ant- a r c t i c a i n order to study the water budget and determine a snow accumulation map of A n t a r c t i c a i n s o f a r as p o s s i b l e . 2. Personnel. R.P. Goldthwaite was p r o j e c t s u p e r v i s o r ; W i l l i a m V i c k e r s was the p r i n c i p a l i n v e s t i g a t o r . 3. R e s u l t s . I t was found to be p o s s i b l e to t r a c e over con s i d e r a b l e d i s t a n c e s b u r i e d f i r n l a y e r s which could be dated m the L i t t l e America r e g i o n from weather markings, such as c r u s t s from super-cooled r a i n for which the h i s t o r y of formation and subsequent metamorphosis had been recorded. An a d d i t i o n a l a i d to t r a c i n g from a c o n t r o l l e d area was devised from a s t a t i s t i c a l a n a l y s i s of g r a m s i z e d i s t r i b u t i o n w i t h i n given l a y e r s . A code for a 650 IBM computer was w r i t t e n t h a t accommodated 20,000 g r a i n s i z e measure- ments, frequency d i s t r i b u t i o n curves were p l o t t e d and goodness-of-fit t e s t s a p p l i e d to determine q u a n t i t a t i v e l y the p r o b a b i l i t y that given samples were from the parent m a t e r i a l assumed, i . e . , the l a y e r being t r a c e d . Further a i d to t r a c i n g and dating v e r i f i c a t i o n was provided by deuteruim a n a l y s i s of summer and w i n t e r l a y e r s (Claude L o r i u s , V i c t o r i a P l a t e a u ) , by e x c a v a t i o n to the known 1939-40 l a y e r a t the b u r i e d camp s i d e of L i t t l e America I I I ; by c o r r e l a t i o n of main s t a t i o n stake farm records w i t h the m e t e o r o l o g i c a l c h a r t s of the IGY p e r i o d . T h i s l a t t e r c o r r e l a t i o n , when viewed i n l i g h t of the s t r a t i g r a p h i c r e c o r d , enabled the d i s t r i b u t i o n of accumulation i n space and time to be d e s c r i b e d for Western Antarc- t i c a , Some of the major c o r r e l a t i o n s derived were: a. G e n e r a l l y , an i n v e r s e r e l a t i o n s h i p e x i s t s between the s t r e n g t h of the i n l a n d high and periods of heavy s n o w f a l l . An example of t h i s i s a r e l a t i v e l y g r e a t e r r a t e of accumulation i n l a t e summer-early f a l l for the V i c t o r i a and P o l a r P l a t e a u s when the s t r e n g t h of the i n l a n d high i s a t a minimum. T h i s c o r r e l a t i o n i s q u i t e marked i n February. Moisture-bearing cyclone p e n e t r a t i o n i n t o the continent i s a t a maximum a t t h i s time. b. An accxjtmulation d i s p a r i t y between the Ross I c e S h e l f , the Byrd S t a t i o n a r e a , and the F i l c h n e r I c e S h e l f d e f i n i t e l y c o r r e l a t e s i n space and time w i t h the presence of an apparent Rex-type blocking high which forms over the B e l l i n g s h a u s e n Sea-Palmer Pen i n s u l a maritime region. T h i s high has the e f f e c t of preventing the eastward migra- t i o n of the Ross Sea Low which then proceeds to p r e c i p i t a t e i n the v i c i n i t y of L i t t l e America f o r s e v e r a l days, g i v i n g a large plus anomaly i n the L i t t l e America record when compared a g a i n s t the area e a s t of Byrd. From Byrd S t a t i o n eastward the e f f e c t i s c l e a r weather, i n accordance w i t h the d i v e r g i n g a n t i c y c l o n i c a i r stream. The blocking e f f e c t of t h i s system has l a s t e d more than a month i n the l a t e w i n t e r - e a r l y s p r i n g season. c. An Ellsworth-Maudheim accumulation d i s p a r i t y i s a t t r i b u t a b l e to E l l s w o r t h being i n a p r e f e r r e d break-out p o s i t i o n f o r the i n l a n d high which keeps c y c l o n i c systems to seaward as they pass to the north of E l l s w o r t h , but a l l o w s them to r e a c h the c o a s t a t Maudheim. 4. Bibliography. W.W. V i c k e r s : "Conformation of S t r a t i g r a p h i c C o r r e l a t i o n s m the F i r n i n Western A n t a r c t i c a . " A n t a r c t i c Symposium, Buenos A i r e s , Nov. 1959 (Pub. i n Monograph No. 5, lUGG, P a r i s , June 1960). 728
INTERDISCIPLINARY RESEARCH W.W. V i c k e r s : "The Use of S t a t i s t i c a l A n a l y s i s i n the T r a c i n g of F i r n L a yers i n A n t a r c t i c a . " X l l t h Gen. Assem., lUGG, H e l s i n k i , 1960 (Pub. i n Pub. No. 55, lASH, Symposium on A n t a r c t i c G l a c i o l o g y , pp. 71-76). W.W. V i c k e r s : "The Annual Rate of I c e Accumulation i n Western A n t a r c t i c a . " Ph.D. D i s s e r t a t i o n , Ohio State U n i v e r s i t y , 1961. 729
INTERDISCIPLINARY RESEARCH P r o j e c t 21.13 - A n a l y s i s of A n t a r c t i c Micrometeorological Data 1. O b j e c t i v e s . T h i s work, administered through the Ohio State U n i v e r s i t y Research Foundation and c a r r i e d out a t the Quartermaster Corps Research and Engineering Center, was organized to provide f o r r e d u c t i o n and d e t a i l e d a n a l y s i s of micrometeorological data c o l l e c t e d m A n t a r c t i c a . Owing to the absence of d i r e c t d i u r n a l i n f l u e n c e s , i t was b e l i e v e d that the a n t a r c - t i c data would lend i t s e l f to a determination of the i n t e r r e l a t i o n s h i p s between wind and temperature p r o f i l e s f o r strong i n v e r s i o n s above uniformly smooth s u r f a c e a r e a s of large e xtent. Consequently, computations were to be made of Richardson numbers. Deacon numbers, roughness parameters, and s u r f a c e shear s t r e s s e s . I t was a l s o planned to com- pute the v e r t i c a l t r a n s f e r of s e n s i b l e heat and to r e l a t e i t to g e n e r a l m e t e o r o l o g i c a l and s u r f a c e c o n d i t i o n s . F i n a l l y , temperature p r o f i l e data were to be analyzed i n order to determine a climatology of the a i r temperature m the eight-meter s u r f a c e l a y e r - the environmental l a y e r . 2. Personnel. R.P. Goldthwait, Ohio S t a t e U n i v e r s i t y , was p r o j e c t s u p e r v i s o r ; P.C. Dalrymple, Quartermaster Corps Research and Engineering Center, was the p r i n c i p a l i n v e s t i g a t o r , Sarah H. Wollaston, micrometeorologist, conducted the a n a l y s i s ; Heinz L e t t a u was c o n s u l t a n t to the p r o j e c t . 3. R e s u l t s . At L i t t l e America, (1957) 1145 hourly wind p r o f i l e s were measured on 157 days, and temperature p r o f i l e s were measured for approximately 3000 hours on 150 days. At the South Pole, (1958) 1416 hourly wind p r o f i l e s were measured on 303 days and temperature p r o f i l e s were measured for approximately 8750 hours on 278 days. These data have been studied a t the Quartermaster Research and Engineering Center, Natick, Massachusetts, under two separate NSF grants administered by The Ohio S t a t e U n i v e r s i t y Research Foundation. Temperature p r o f i l e measurements from seven depths and ten heights w i t h i n e i g h t meters of the s u r f a c e have been transformed from m i l l i v o l t readings on s t r i p c h a r t s to degrees Centigrade on punch c a r d s . The data r e d u c t i o n was accomplished through a system s p e c i a l l y designed for the p r o j e c t . T a b u l a t i o n s of these data (105,080 IBM cards of L i t t l e America V p r o f i l e data, 210,622 IBM cards of South Pole p r o f i l e data) were c r i t i c a l l y reviewed and e d i t e d , and summary and mean cards were computed f o r each hour and day. Wind p r o f i l e s were computed i n centimeters per second for s i x heights (50 centimeters to e i g h t meters) and were punched onto IBM cards (517 IBM cards for L i t t l e America; 1088 IBM cards for South P o l e ) . * Using periods when both wind and temperature p r o f i l e s were a v a i l a b l e , 1050 R i c h a r d - son number p r o f i l e s were computed f o r the South Pole and 580 Richardson number p r o f i l e s were computed for L i t t l e America V. At the South Pole, the bulk s t a b i l i t y , R i ' ( R i ' Z R I / Z Z , expressed m 10"3 per one meter) for 50-centimeter to eight-meter l a y e r , ranged from -24 to +110. Cases of negative R i ' ( l a p s e c o n d i t i o n s ) were i n f r e q u e n t , but occurred i n A p r i l during the period without s o l a r h eating (overrunning warm a i r and i t s long-wave r a d i a t i o n ) as w e l l as during the period w i t h sun. A p l o t of Richardson number versus height f o r s e l e c t e d 10-run and 30-run groups (670) p r o f i l e s ) i s shown i n F i g u r e 23. A systematic change of R i ' w i t h height i n the lowest four meters i s e v i d e n t . A check was made of se a s o n a l v a r i a t i o n s i n average s t a b i l i t y . For the period of r e c o r d , February through November, the months w i t h low s t a b i l i t y , as measured by R i ' , were February, May, and November. The curvature of wind and temperature p r o f i l e s i s measured by the Deacon numbers (Pv and Pg). The height v a r i a t i o n of Pv and Pg f o r v a r i o u s c l a s s e s of s t a b i l i t y a t the South Pole I S shown i n F i g u r e 24. A h i g h l y i n t e r e s t i n g and s i g n i f i c a n t r e l a t i o n i s evident between the wind p r o f i l e Deacon number, fnj, and the Richardson number. I n * Wind and temperature p r o f i l e data are a v a i l a b l e i n South Pole Micrometeorological Program, P a r t I - Data P r e s e n t a t i o n , ES-2, QM R&E. 730
INTERDISCIPLINARY RESEARCH 10 lUN 10 lUN miAv F i g u r e 23, R i versus height f or i n d i c a t e d R i ' , Bs> Alogai-AloflA9 F i g u r e 24. South Pole - Bv and Be versus height for i n d i c a t e d R i ' . 731
INTERDISCIPLINARY RESEARCH s t a b l e c a s e s , Pv, decreased w i t h height. However, ^ does not become zero but, even w i t h great s t a b i l i t y , goes only to approximately 0.25 and then r e c u r v e s . T h i s r e c u r v a - ture i s most l i k e l y due to v e r t i c a l g r a d i e n t of s h e a r i n g s t r e s s . The temperature pro- f i l e Deacon number, when p l o t t e d a g a i n s t height, i s s i m i l a r to only a t very low height (Figure 2 4 ) . However, does become zero and even negative w i t h g r e a t s t a b i l i t y a t l e v e l s above one to two meters. The wind p r o f i l e Deacon number, Py, was p l o t t e d a g a i n s t the l o c a l Richardson number, R i . A t h e o r e t i c a l r e l a t i o n s h i p * * ^ = (1 - 7 ' R i ) / ( l - 0.75 y ' R i ) where y' 18, d e s c r i b e s the data w e l l for s l i g h t l y s t a b l e c o n d i t i o n s , but predictsp^, < 0 i f R i > l / 7 ' = 0.0555. As shown i n F i g u r e 2, the observed Pv does not become zero as R i i n c r e a s e s , but recurves and i n c r e a s e s again beyond R i = 0.15. T h i s i l l u s t r a t e s the e f f e c t of divergence of momentum f l u x . A method of wind p r o f i l e a n a l y s i s was introduced which permits computation of ZQ for (Pv-1 as a l i n e a r f u n c t i o n of height. Roughness length, ZQ, was n e a r l y constant a t 0.014 cm for n e u t r a l and moderate s t a b i l i t y , ZQ values that i n c r e a s e d s l i g h t l y w i t h both i n s t a b i l i t y and extreme s t a b i l i t y are questionable because of the s m a l l number of c a s e s . However, ZQ does i n c r e a s e under unstable c o n d i t i o n s when wind speed i s high enough (about 13 m/s a t 8 m) to produce an i n c r e a s e of p^ w i t h height throughout the 50-centimeter to eight-meter l a y e r . The flow i s then f u l l y rough, w h i l e the flow appears to be c l o s e to the c o n d i t i o n of being aerodynamically smooth for the m a j o r i t y of s t a b l e c a s e s . The low value of Z g i s c o n s i s t e n t w i t h other measurements over snow. S a s t r u g i g r e a t e r than 20 cm were always removed 30 f e e t upwind from the mast. I t was p o s s i b l e to improve the r e g u l a r i t y of some of the p^ curves by applying a zero displacement parameter, D, to c o r r e c t for i r r e g u l a r i t i e s of the s u r f a c e i n the d i r e c t i o n from which thewmd was blowing. D was o c c a s i o n a l l y as large as 15 cm f o r the grouped p r o f i l e s and could be e i t h e r p o s i t i v e or negative. The s u r f a c e s t r e s s , "^o, computed f o r the grouped data, was r e l a t i v e l y low, i t ranged from 0.103 dynes per cm2 a t R i ' = 89 to 0.825 a t R i ' = 10. The drag c o e f f i c i e n t (as defined hyy/\JplVi^) was n e a r l y independent of s t a b i l i t y and averaged 0.039. Eddy heat f l u x , QQ, was computed using a s i m i l a r i t y r e l a t i o n , QQ = -CpToAg/AV. The heat t r a n s f e r c o e f f i c i e n t , as defined by K 2,0.5 -Qo/cpp(V2 - V o.5)(02 " 90.5>> computed from the p r o f i l e decreased w i t h s t a b i l i t y , as measured by R i ' , but not i n a l i n e a r r e l a t i o n ; for example- 02,0.5 i s 0.130, 0.058 and 0.027 for R i ' -24, 19, and 89, r e s p e c t i v e l y . Running means of temperature, centered on 24 equally-spaced dates throughout the year, were p l o t t e d a g a i n s t time for +200 cm, the s u r f a c e , and -10, -25, -50, and -250 cm. Summer temperatures were i n t e r p o l a t e d , but i t was p o s s i b l e to study the w i n t e r minima for that p a r t i c u l a r year. T r i p l e minima occurred a t +200 cm, s u r f a c e , -10, -25, and -50 cm. There was a s i n g l e minimum for -250 cm, which occurred i n l a t e September. Subsurface temperatures were a l s o shown as isotherms w i t h coordinates of time v s . depth and by p l o t t i n g tautochrones showing temperature v s . depth a t a given time. Harmonic a n a l y s i s of subsurface temperatures a t nine depths showed a g e n e r a l l y uniform i n c r e a s e w i t h dep'th i n the amplitude and phase angle of the f i r s t and second harmonic. Thermal d i f f u s i v i t y and heat c o n d u c t i v i t y were obtained as f u n c t i o n s of depth. I t was found that the a c t u a l heat f l u x m the upper 3 to 4 meters of snow i s !.-* See Panofsky, Blackadar, McVehil, The D i a b a t i c Wind P r o f i l e , Quart. J . Roy. Meteor. S o c , V86, 1960, p. 86- 390-398. 732
INTERDISCIPLINARY RESEARCH only p a r t l y p r o p o r t i o n a l to the v e r t i c a l temperature g r a d i e n t . Heat storage curves as part of the c a l c u l a t i o n of the heat budget f o r the South Pole are c u r r e n t l y being e v a l - uated. The a n a l y s i s of the South Pole data, p a r t i c u l a r l y i n r e l a t i o n to the heat balance a t the s u r f a c e , was completed under an NSF grant (No. G19603) administered by the Ohio State U n i v e r s i t y Research Foundation, and a s c i e n t i f i c r e p o r t published by the Quarter- master Research and Engineering Center. The climatology of the environmental l a y e r of the atmosphere a t both L i t t l e America V and the South Pole were studied by the Quartermaster Corps. A sub-contract was completed by The U n i v e r s i t y of Michigan on the h e a t - t r a n s f e r c h a r a c t e r i s t i c s of the thermocouple probes used a t the South Pole. 4. Bib l i o g r a p h y . P.C. Dalrymple: " F i r s t R e s u l t s from the U.S, Army Quartermaster Corps Micro- meteor o l o g i c a l Program i n the A n t a r c t i c During the IGY." Presented a t the X l l t h General Assembly, lUGG, H e l s i n k i , 1960. P.C. Dalrymple: "South Pole Micrometeorological Program, P a r t I - Data Presen- t a t i o n . " T e c h n i c a l Report ES-2, Quartermaster Research and Engineering Center, Natick, Massachusetts, October 1961. D.J. Portman- "An I n v e s t i g a t i o n of Some H e a t - t r a n s f e r C h a r a c t e r i s t i c s of Two Thermocouple Probes." Meteorological L a b o r a t o r i e s , Dept. of Engineering Mechanics, College of Engineering, The U n i v e r s i t y of Michigan, F i n a l Report, National Science Foundation IGY Grant Y/21.13/336, Off. of Res. A d m i n i s t r a t i o n , Ann Arbor, Mich., Sept. 1961. 733
INTERDISCIPLINARY RESEARCH P r o j e c t 21.14 - A n a l y s i s of Heat Budget Data of S t a t i o n Alpha 1. O b j e c t i v e s . During the IGY, temperature data were gathered a t S t a t i o n Alpha from the snow i c e s u r f a c e , from the atmosphere m the f i r s t few meters above the s u r f a c e , from the pack i c e and from the ocean water j u s t below the pack i c e . The data extend over two complete melt-seasons, one complete winter season and part of another. These, along w i t h s o l a r r a d i a t i o n , evaporation, condensation, melting, s u r f a c e parameter, i c e t h i c k n e s s , and drainage data, w i l l be analyzed to study i n p a r t i c u l a r the t r a n s f e r of heat a c r o s s the snow-ice-air boundary. Each process of energy ex- change w i l l be analyzed s e p a r a t e l y , the papers r e s u l t i n g w i l l be both d e s c r i p t i v e and q u a n t i t a t i v e on such t o p i c s a s : a. T o t a l s o l a r r a d i a t i o n absorbed (summer seasons) b. Net r a d i a t i o n balance (winter and summer seasons) c. Evaporation and condensation (winter and summer seasons) d. Turbulent exchange of energy (winter and summer seasons) e. The co l d ( a i r ) l a y e r (winter season) f. T o t a l melt (summer seasons) g. Temperature g r a d i e n t s i n the atmosphere (winter and summer seasons) h. Wind p r o f i l e s ( winter and summer seasons) i . Thermal g r a d i e n t s i n the pack-ice (winter and summer seasons) j . Thermal c o n d u c t i v i t y of the pack-ice (winter and summer seasons) k. Thickening of the pack-ice (winter and summer seasons) 2. Personnel. P.E. Church was p r o j e c t d i r e c t o r f or t h i s work, the p r i n c i p a l s c i e n t i s t s were F . I . Badgley, and Norbert U n t e r s t e i n e r . 3. R e s u l t s . From h i s a n a l y s i s of the A r c t i c Ocean data, U n t e r s t e i n e r found that measurements during the d r i f t of "U.S. D r i f t i n g S t a t i o n A" show an annual mass i n c r e a s e of old i c e c o n s i s t i n g of 12.5 g/cm^ snow and 52 g/cm2 bottom a c c r e t i o n . During the summer seasons 1957 and 1958 an amount of 19.2 and 41.4 g/cm2, r e s p e c t i v e l y , was l o s t by s u r f a c e a b l a t i o n . The r a t i o of a b l a t i o n on e l e v a t e d "dry" s u r f a c e and i n meltwater ponds I S 1:2.5. The average pond area was about 307,. Bottom - b l a t i o n by heat t r a n s f e r from the ocean was found to be 22 cm ( J u l y to Aug./Sept.). Methods of measuring mass changes are d e s c r i b e d . I n view of t h e i r importance as a means of checking the computed heat budget t h e i r accuracy i s d i s c u s s e d i n d e t a i l . The heat budget i s computed f o r a s e l e c t e d period during the height of the melt season. The average d a l l y t o t a l s a r e , i n cal/cm2: +142 from n e t s h o r t wave r a d i a t i o n , -8 from net long wave r a d i a t i o n , +9 from t u r b u l e n t heat t r a n s f e r , and -11 from evapora- t i o n . The mean d a i l y s u r f a c e a l s l a t i o n i s 0,8 cm. About 90% of i t i s due to the absorp- t i o n of sho r t wave r a d i a t i o n . Only 62% of the t o t a l heat supply a re transformed a t the s u r f a c e . 38% are t r a n s - mitted i n t o the i c e and mainly used to i n c r e a s e the b r i n e volume. The v e r t i c a l d i s t r i - b u tion of t h i s energy was used to compute the e x t i n c t i o n c o e f f i c i e n t f o r shor t wave r a d i a t i o n . From 40 to 150 cm depth i t i s 0,015 cm"!, somewhat s m a l l e r than t h a t of g l a c i e r i c e . The heat used during the summer to i n c r e a s e the b r i n e volume i n the i c e a c t s as a r e s e r v e of l a t e n t heat during the c o o l i n g season. By the time an i c e sheet of 300 cm th i c k n e s s reaches i t s minimum temperature i n March, 3000 cal/cm2 have been removed to fre e z e the b r i n e i n the i n t e r i o r of the i c e and the meltwater ponds, and 1700 cal/cm2 to lower the i c e temperature. Based upon the observed mass and temperature changes the t o t a l heat exchange a t the upper and lower boundary i s estimated. During the period 734
INTERDISCIPLINARY RESEARCH May-August the upper boundary received 8.3 kcal/cm2, while during the period September- A p r i l 12.8 kcal/cm2 were transmitted t o the atmosphere. Considerable disagreement was found i n comparison w i t h Soviet r e s u l t s w i t h respect to the amounts of heat involved i n evaporation and i n changes of ice temperature (heat reserve). I n a f u r t h e r study, Untersteiner integrated numerically equation of heat conduction, i n c l u d i n g v a r i a b l e thermal c o n d u c t i v i t y and s p e c i f i c heat, and i n t e r n a l heat source diminishing w i t h depth, and an advective term, f o r the case of sea ice of e q u i l i b r i u m thickness, w i t h the annual cycle of thickness ( a b l a t i o n - a c c r e t i o n ) imposed as an ex- t e r n a l parameter. The boundary values f o r temperature, and the v e r t i c a l d i s t r i b u t i o n of ice s a l i n i t y were taken from e m p i r i c a l data. The computed temperature f i e l d i s i n good agreement w i t h observations. The thermal h i s t o r y of i n d i v i d u a l p a r t i c l e s of i c e , the r e l a t i v e e f f e c t of the i n t e r n a l heat source (penetrating solar r a d i a t i o n ) , heat storage, and the annual cycle of heat f l u x by conduction a t various depths are de- scribed. The observed maximum of b r i n e volume a t 40-70 cm depth i s explained as the combined e f f e c t of s a l i n i t y p r o f i l e and i n t e r n a l absorption of r a d i a t i o n . The req u i r e - ment th a t heat f l u x i n the ice plus the heat equivalent of surface a b l a t i o n equal the heat f l u x i n the atmospheric boundary layer i s w e l l met by Badgley's values of r a d i a t i v e and t u r b u l e n t heat t r a n s f e r . During the melting season, June 15 to August 20, the surface of the ice received about 4.5 kcal/cm2 and loses, during the freezing season, August 21 to June 14, an only s l i g h t l y greater amount of heat to the atmosphere. The annual sum of heat conduction a t the base of the ice i s 3.6 kcal/cm2. 2.0 kcal/cm2 o r i g i n a t e from ice a c c r e t i o n , and 1.6 kcal/cm2 are drawn from the ocean. The atmosphere over the Central A r c t i c received an annual t o t a l of 2.5 kcal/cm2 which i s mainly the heat of f u s i o n of exported i c e . From his analysis of the data, Badgely found t h a t a resume of a v a i l a b l e data on the components of the heat budget of the A r c t i c Ocean surface shows th a t r a d i a t i v e interchange w i t h the environment i s the dominant f a c t o r . The presence or absence of an ice cover influences the nature of t h i s interchange and also the r e l a t i v e importance of evaporation to the heat budget. On the basis of these f i g u r e s a conjecture i s made as to the course of events i n the event of the a r t i f i c i a l removal of the ice cover. I t has been occasionally proposed t h a t i f the present ice sheet were destroyed, i t would not spontaneously reappear and the A r c t i c Ocean would remain open. This i s based on the assumption t h a t the low albedo of the open water would allow enough energy to be absorbed during the summer so t h a t ice would not r e - e s t a b l i s h i t s e l f w i t h s u f f i c i e n t thickness to be s e l f - s u s t a i n i n g during the coming year or years. The analysis of the data raise doubts t h a t t h i s would be true but they cannot be said to disprove the p o s s i b i l i t y . I f the ocean, or large parts of i t , were fre e of ice many of the assvmiptions used would be i n v a l i d . One way to reach a reasonable estimate of the o v e r - a l l e f f e c t i s to postulate f o r the winter months a purely r a d i a t i v e exchange between the ocean surface a t about O'C and an opaque atmospheric layer ( i d e a l i z e d cloud l a y e r ) a t some lower temperature which i s to be computed. This cloud layer i s to remain i n qu a s l - e q u l l i b r i u m between the energy i t gains and loses by r a d i a t i o n and t h a t which i t gains by advection from out- side the a r c t i c . This advective term remains the same as i t i s a t present, about 1022 c a l o r i e s per year. When t h i s computation i s c a r r i e d out i t shows a net loss of .155 cal/cm2min or 6,7 x 103 cal/cm2mo. This f l u x i s enough to remove a l l the excess energy supplied by the sun over a period of about 10 months. I n the succeeding two months an ice cover could r e - e s t a b l i s h i t s e l f . Just how t h i c k t h i s might become before the next melt season i s problematical but thicknesses of a meter or more could be expected. With an ordinary snow cover t h i s thickness of ice could e a s i l y maintain i t s e l f f o r f u t u r e seasons. I t has also been suggested t h a t an increased flow of A t l a n t i c water i n t o the A r c t i c Ocean would d i s s i p a t e the ice cover* This IncreHsed flow could concelvHbly occur 735
INTERDISCIPLINARY RESEARCH n a t u r a l l y or be produced by pumping water across an a r t i f i c i a l b a r r i e r a t Bering S t r a i t s . I t may be somewhat obvious t h a t the ice f l o e s w i l l approach some l i m i t i n g thickness which depends on the net heat flow out the top and i n a t the bottom. When these two are balanced over a long period of time the ice w i l l be i n a quasi-steady s t a t e . I f the i n f l u x of heat at the bottom were increased, the f l o e would t h i n u n t i l a new e q u i l i b r i u m was reached. I n order f o r the ice to disappear i n the summer i t should not be much more than 1/2 meter t h i c k , one-sixth of i t s present thickness. Assuming t h a t the snow cover, which represents about 1/3 of the resistance to heat f l o w , would remain unchanged, t h i s means th a t the t o t a l resistance to heat flow would be reduced to 4/9 of I t s present value. This would mean th a t the heat flow from the ocean should be increased by 9/4 of 2.25 times i t s present value, an increase of approximately .004 cal/cm2min. Assuming A t l a n t i c water were drawn i n a t +1°C and discharged a t -1.7°C t h i s would c a l l f o r an increased flow of 2.4 + lO^m^/min; equivalent to a r i v e r a mile wide and 200 f e e t deep flowing a t about 1-1/2 miles per minute. The conclusion i s t h a t no a r t i f i c i a l means i s f e a s i b l e to produce the desired e f f e c t . I t i s conceivable t h a t some n a t u r a l cause could increase the present flow by a f a c t o r of two or three and thereby cause the d i s s i p a t i o n of the ice but t h i s remains i n the realm of conjecture. 4. Bibliography. F . I , Badgley: "Heat Balance a t the Surface of the A r c t i c Ocean." Presented at the Washington Snow Conference, S e a t t l e , 1961 (a v a i l a b l e i n mimeographed form from Department of Meteorology and Climatology, Univ. of Washington). Norbet Untersteiner: "On the Mass and Heat Budget of A r c t i c Sea Ice." Arch, f u r Met.. Geoph., Bioklimat., Serie A, Band 12, 2.Heft, 1961. Norbet Untersteiner: "Calculations of Temperature Regime and Heat Budget of Sea Ice i n the Central A r c t i c . " JGR, v o l . 69, no. 22, November 15, 1964, pp. 4755-4766. N. Untersteiner and F. I . Badgley. "The Roughness Parameter of Sea I c e . " JGR. Vol. 70, No. 18, September 15, 1965, pp 4573-4577. 736
INTERDISCIPLINARY RESEARCH Project 21.15 - Analysis of G l a c i a l Geological Data from Spitsbergen 1. Objectives. This p r o j e c t a t the I n s t i t u t e of Polar Studies, Ohio State U n i v e r s i t y , provided f o r the analysis of data c o l l e c t e d during the Swedish G l a c i o l o g i c a l Expedition to Nordaustlandet, Spitsbergen i n which the p r i n c i p a l i n v e s t i g a t o r p a r t i c i p a t e d . The c h i e f aim of the research was to e s t a b l i s h a g l a c i a l chronology f o r l a t e Pleistocene and Recent time i n northeastern Spitsbergen. 2. Personnel. R.P. Goldthwait was p r o j e c t supervisor; the p r i n c i p a l i n v e s t i g a t o r was Weston Blake, J r . 3. Results. During the summers of 1957 and 1958, the p r i n c i p a l i n v e s t i g a t o r c o l l e c t e d s h e l l s , whale bones, and driftwood f o r d a t i n g , observed raised beaches and other land- forms f o r evidence of r a t e of land u p l i f t f o l l o w i n g recession of the ice sheet, inves- t i g a t e d marginal g l a c i e r f l u c t u a t i o n s , and studied the patterned ground and other features of t h i s area. Most of the data analyzed under t h i s p r o j e c t r e l a t e d to the dating of various i n f e r r e d sea levels i n an e f f o r t to e s t a b l i s h the r a t e of u p l i f t . From radiocarbon dates on d r i f t w o o d , whale bones and s h e l l s , an e l e v a t i o n vs. age curve was constructed t h a t c a r r i e d back to about 10,000 years before the present. There was no m a t e r i a l c o l l e c t e d w i t h dates between 10,000 and more than 35,000 years ago, leading to the inference t h a t during t h i s period the land was glacier-covered. The slope of the elevation/age curve changes sharply at about 8,000 years, and i t i s i n f e r r e d that the u p l i f t i n very recent time i s q u i t e small, not exceeding a few c e n t i - meters per 100 years. This conclusion i s supported by the f a c t t h a t on a low i s l a n d facing the open sea a Russian hunter's s h e l t e r was found t h a t i s now only 0.7 meters above the l e v e l of the highest t i d e s , and the s h e l t e r i s a t least 100 years o l d . One t i d a l o u t l e t g l a c i e r i n the f i e l d area r e t r e a t e d about 2.8 kilometers between 1899 and 1938, but I t has since become more ac t i v e and has advanced s l i g h t l y . Lichenological studies a t the edge of Vestfonna i n d i c a t e , however, th a t the main body of t h i s icecap has not advanced beyond i t s present p o s i t i o n f o r a t least 2,000 years. From September 1958 to December 1961 the p r i n c i p a l i n v e s t i g a t o r analyzed data and prepared reports on a part-time basis, from November 1959 to December 1961 under Project 21.15. Part of the work has been done at The Ohio State U n i v e r s i t y , part a t the Uni- v e r s i t y of Stockholm. The f i n a l r e p o r t was published as one of a series of expedition reports i n the Swedish j o u r n a l "Geografiska Annaler." 4. Bibliography. W. Blake, Jr.- "Swedish G l a c i o l o g i c a l Expedition to Nordaustlandet." 1957, Polar Record, v o l . 9, no. 59, 1958, pp. 142-43. W. Blake, J r . : "Swedish G l a c i o l o g i c a l Expedition to Nordaustlandet." 1958, Polar Record, v o l . 9, no. 61, 1959, pp. 339-40. W. Blake, J r . : "The Late Pleistocene Chronology of Nordaustlandet, Spitsbergen." Abstracts of Papers, 19th I n t e r n a t i o n a l Geographical Congress, Stockholm, Sweden, 1960, pp. 26-27. W. Blake, J r . : "Russian Settlement and Land Rise i n Nordaustlandet, Spitsbergen," A r c t i c , v o l . 14, no. 2, 1961, pp. 101-11. W Blake, J r . : Radiocarbon Dating of Raised Beaches i n Nordaustlandet, Spits- bergen." Geology of the A r c t i c . (Proc. of F i r s t I n t . Symp. on A r c t i c Geology). Univ. of Toronto Press, 1961, pp. 133-45. 737
INTERDISCIPLINARY RESEARCH W. Blake, J r . : "Patterned Ground i n Nordaustlandet, Spitsbergen." Abstracts of Papers. 6th INQUA Congress, Warsaw, Poland, 1961, p. 88. I n g r i d Olsson and Weston Blake, J r . : "Problems of Radiocarbon Dating of Raised Beaches, Based on Experience i n Spitsbergen." Norsk Geografisk T i d s s k r i f t . v o l . 18, no. 1-2, 1961-1962. 738
INTERDISCIPLINARY RESEARCH Project 22.1 - Ionospheric Dynamics 1. Objectives. This work a t the Rand Corporation was aimed a t f u r t h e r i n g understanding of atmospheric motions i n the high atmosphere, r e l a t e d t o the n e u t r a l component (winds) and the ionized component ( e l e c t r i c c u r r e n t s ) . As the work progressed, consideration was also given to the motions of charged p a r t i c l e s trapped i n the geomagnetic f i e l d . IGY data i n the f i e l d s of geomagnetism, meteorology, ionospheric physics, aurora and solar a c t i v i t y were used i n these studies. 2. Personnel. E.H. Vestine and W.W. Kellogg were the senior s c i e n t i s t s associated w i t h t h i s p r o j e c t ; c o n t r i b u t i o n s were also made by J. Kern, E.S Batten, R.R. Rapp, and W.L. Sibley. 3. Results. Since a large number of problems were considered i n association w i t h t h i s p r o j e c t , i t i s not possible to summarize a l l the papers or reports produced. I n connection w i t h the newly emerging technique of meteorological observations above balloon a l t i t u d e s by the use of small rockets, Rapp analyzed the accuracy of wind deter- minations made using radar t r a c k i n g of c h a f f . I n a more general study. Batten and Kellogg summarized a v a i l a b l e wind and temperature data below 100 km i n an attempt to deduce general features of the atmospheric c i r c u l a t i o n . This has led t o the study of the heat budget of t h i s p art of the atmosphere. I t was shown th a t chemical energy must be an important f a c t o r i n the warming of the mesosphere served i n w i n t e r . Vestine and Sibley studied a u r o r a l isochasms i n the l i g h t of mapping the curves of equal I ( i n t e g r a l i n v a r i a n t ) of a u r o r a l p a r t i c l e motion. They found t h a t a u r o r a l i s o - chasm ( l o c i of points of equal a u r u r a l occurrence) and older data on perpendiculars to average d i r e c t i o n s of a u r o r a l arcs f i t t e d the I curves w e l l . I t was concluded t h a t corresponding isochasms of the Northern and Southern hemispheres should be l i n k e d by geomagnetic f i e l d l i n e s , even though the respective m i r r o r points do not always occur at a u r o r a l l e v e l s . I t was also concluded that d r i f t motions of p a r t i c l e s e n tering the geomagnetic f i e l d are important m ex p l a i n i n g some a u r o r a l features. I n a f u r t h e r a p p l i c a t i o n of t h i s concept, Vestine noted t h a t , assuming t h a t the solar wind compressed the f i e l d a t the noon meridian and elongates the f i e l d l i n e s on the ni g h t side of the e a r t h , i t i s possible to e x p l a i n how p a r t i c l e s move to lower f i e l d l i n e s - to conserve I - producing m i r r o r points lower i n the atmosphere, i n f a c t , i n the region where au r o r a l e x c i t a t i o n could occur. This e f f e c t would tend to e x p l a i n the increased frequency and i n t e n s i t y of the aurora a t n i g h t , the polar e l e c t r o j e c t s associated w i t h polar magnetic disturbances and radio blackout, and the tendency f o r magnetic bays to recur near the same time UT f o r several consecutive n i g h t s . Taking i n t o account the s p h e r i c a l harmonic expansion of the geomagnetic f i e l d and assuming that the e x t e r n a l c o n t r i b u t i o n to the f i e l d as observed a t the earth's surface cannot have a value i n excess of the averaged errors i n the isomagnetic charts that were analyzed, Vestine ( c o l l a b o r a t i n g w i t h A.J. Dessler) computed t h a t the maximum energy of geomagnetically trapped charged p a r t i c l e s i s approximately 6 x 10^5 j o u l e s . I t I S i n t e r e s t i n g to note that t h i s amount of energy can be accounted f o r by only 5 X 10^ electrons per cm-* of an average energy of 40 kev d i s t r i b u t e d throughout a volume of s i x earth r a d i i . 4. Bibliography. E.H. Vestine, W.L. S i b l e y "Remarks on Auroral Isochasms." JGR, v o l . 64, no. 9, 1959, pp. 1338-39, E.H. Vestine: "The Survey of the Geomagnetic F i e l d i n Space." Rand Report P-1863-NSF, Jan. 5, 1960. 739
INTERDISCIPLINARY RESEARCH E.H. Vestine: "Polar A u r o r a l , Geomagnetic, and Ionospheric Disturbances." JGR, v o l . 65, no. 1, 1960, pp. 360-61. A.J. Dessler, E.H. Vestine: "Maximum T o t a l Energy of the Van A l l e n Radiation B e l t s . " JGR, v o l . 65, no. 3, 1960, pp. 1069-71. J.W. Chamberlain, J. Kern. E.H. Vestine: "Some Consequences of Local Accelera- t i o n of Auroral P a r t i c l e s . " JGR, v o l . 65, no. 8, 1960, pp. 2535-37. E.H. Vestine: "Note on the D i r e c t i o n of High Auroral Arcs." JGR, v o l . 65, no. 10, 1960, pp. 3169-77. 740
INTERDISCIPLINARY RESEARCH Project 22.2 - Analysis of Solar Phenomena and Radio Noise 1. Objectives. This p r o j e c t a t the Rensselaer Polytechnic I n s t i t u t e was concerned w i t h the analysis of 18 Mc cosmic noise absorption (SCNA) and 517 Mc data i n an e f f o r t to i n v e s t i g a t e r e l a t i o n s between SCNA c h a r a c t e r i s t i c s and those of other simultaneously occuring solar-geophysical events. Possible r e l a t i o n s were explored between SCNA's and noise bursts on the one hand and v i s u a l and radio solar phenomena, a u r o r a l and ionospheric, and atmospheric events on the other. Information was sought on el e c t r o n d e n s i t i e s and recombination rates i n the D region a t times of f l a r e s and on t o t a l ionospheric absorption at 18 Mc, i t s seasonal v a r i a t i o n , r e l a t i o n to magnetic i n d i c e s , etc. 2. Personnel. Robert Fleischer was the p r i n c i p a l i n v e s t i g a t o r ; associated w i t h him i n t h i s work were Pearl Lichtenberg and Alan Meltzer. 3. Results. The analysis of 18 Mc/s solar noise data c o l l e c t e d by RPI Radio Obser- vatory during the IGY was divided i n t o two parts concerned r e s p e c t i v e l y w i t h the back- ground noise and special events. Dr. Meltzer worked on problems of the v a r i a t i o n s i n the background noise, and Dr. L i c h t e n s t e i n on the special events. The f o l l o w i n g f a c t s were established: (1) While many solar f l a r e s , e s p e c i a l l y those of importance 1 or 1-, produced no e f f e c t s a t 18 Mc/s, no SCNA was ever found to have occurred i n the known absence of a solar f l a r e , (although one or two events occurred a t times when no v i s u a l observations were av a i l a b l e because of adverse weather c o n d i t i o n s ) . (2) The occurrence of 18 Mc/s solar bursts was confirmed by comparison of data from several s t a t i o n s . No d i s t i n g u i s h i n g c h a r a c t e r i s t i c s could be found be- tween solar f l a r e s which produced 18 Mc/s bursts and those which d i d not. Among the c h a r a c t e r i s t i c s considered were p o s i t i o n of f l a r e on solar d i s k (longitude and l a t i t u d e ) and f l a r e importance. The a c t i v i t y of the sun was so great during t h i s period t h a t on most days there was one f l a r e of a t least 1- importance during each 10-minute i n t e r v a l , and on most occasions a number of such f l a r e s occurred simultaneously or nearly so. As a r e s u l t , an i n d i v i d u a l v i s u a l event can r a r e l y be pinpointed as being responsible f o r the radio event, unless i t i s very large (importance 2 or g r e a t e r ) . An attempt was made to c o r r e l a t e a u r o r a l absorption w i t h v i s u a l aurora. While aurora absorption was observed on most nights of v i s u a l aurora, no agreement was found between times of maximum i n t e n s i t y v i s u a l l y and i n radio e f f e c t . Several of the strongest radio events were found to continue i n t o d a y l i g h t hours. Several events of extreme absorption were observed, leading to s i g n a l blackout f o r a t l e a s t several hours. These are found t o be cl o s e l y r e l a t e d to events observed as PCA's at higher magnetic l a t i t u d e . A t h e o r e t i c a l analysis of expected v a r i a t i o n of absorption w i t h time under c e r t a i n s i m p l i f y i n g conditions was c a r r i e d out and applied t o several observed SCNA events. For convenience i n a n a l y t i c a l s o l u t i o n , only c e r t a i n simple forms of input pulse have been considered. We s h a l l l i m i t our present consideration to a pulse s t a r t i n g from 0 at time t = 0 and reaching a maximum value b a t time t g = T. Since the r e s u l t s t u r n out to be simply p r o p o r t i o n a l to the peak value b, one can without loss of g e n e r a l i t y use a peak value of 1 throughout and t r e a t the r e s u l t s as having an a r b i t r a r y scale. Calculations have been made f o r a wide range of a l l the parameters, w i t h the f o l l o w i n g r e s u l t s : (1) I n every case the greatest absorption occurs l a t e r than the peak of the input pulse, and (2) w i t h only minor exceptions, the absorption near the end o f the SCNA becomes a simple e x p o t e n t i a l decaying as e-a(t - t g ) , so tha t the value of the parameter a determines the shape of the SCNA near i t s end. 741
INTERDISCIPLINARY RESEARCH Lic h t e n s t e i n considered two very d i f f e r e n t observed SCNA's and f i t t e d t h e o r e t i c a l curves to the observations. The f i r s t i s a t y p i c a l SCNA, which occurred October 13, 1958 a t 1640 UT (see F i g . 25). The c i r c l e s represent the observed SCNA, and the s o l i d l i n e the calculated absorption f o r the case t,, =400 s e c , T = 200 s e c , a = 1.5 10-3 sec-1. x The second case (Fig. 26) i s an unusually short but strong SCNA, which occurred a t 1342 UT on March 29, 1958. Here a good f i t i s obtained w i t h to = 100 s e c , T = 50 s e c and a =3.0 x lO'^ sec"!. While the exact values of to and T are not s i g n i f i c a n t , i t i s probably true t h a t the d u r a t i o n of the absorption i s about 3 times as long as t h a t of the i n i t i a t i n g pulse. The most i n t e r e s t i n g r e s u l t i s the value of the parameter a which i s f a i r l y accurately determined. This value probably i s representative of conditions near the bottom of the D-layer, both because the largest c o n t r i b u t i o n to the absorption arises where the c o l l i s i o n c o e f f i c i e n t i s greatest and because as a increases s l i g h t l y toward the top of the layer the absorption from higher levels w i l l tend to damp out more r a p i d l y than that from the bottom. Assuming a value of the e l e c t r o n density before the pulse of 250/co, which i s reasonable f o r a height of 70 km, the recombination r a t e OL becomes 3 X 10*^ cm^ s e c " l , a value considerably larger than t h a t determined from other mea- surements. Using the IBM 650 a t the R.P.I. Computation Laboratory we obtained mean values of si g n a l l e v e l f o r every hour of UT and every hour of s i d e r e a l time. No consistent r e s u l t s could be obtained from these values. I t appears t h a t while r e l a t i v e values of s i g n a l strength f o r any period of a few consecutive days are re- l i a b l e , the zero point of the c a l i b r a t i o n curve d r i f t s and thus causes the average values to be meaningless. For t h i s reason f u r t h e r work on t h i s aspect of the analysis had to be given up. F i n a l l y , a study was also made to determine the possible tropospheric e f f e c t s on the cosmic noise data. Comparison of the 18 Mc records and atmospheric e l e c t r i c a l , p r e c i p i t a t i o n , atmospheric pressure and cloud data revealed t h a t there are o f t e n large apparent SCNA or noise events a t times of meteorological but no solar a c t i v i t y . More than h a l f the time, p r e c i p i t a t i o n a t or i n the l o c a l i t y of the s t a t i o n r e s u l t e d i n lo c a l i z e d absorption or 18 Mc emission. 4. Bibliography. R. Fleischer, R.E. Falconer: "Cosmic Noise and the Weather." Eastern Snow Conference, 1960 (Published as Rens. Obs. Pub. No, 19, October 1960). Pearl R. L i c h t e n s t e i n : " C alculation of Cosmic Radio Noise Absorption Produced by Pulses of I o n i z i n g Radiation." Rens. Obs. Memorandum No. 32, October 1959. 742
INTERDISCIPLINARY RESEARCH 200- Tlme, Minutes = 1*00 seconds C a l c u l a t e d ^ a = I . 5 x lo"^ s e c " ^ = 200 seconds O Observed, Oct. 13, 1958, l61»0 u.T. Figure 25. Sudden Cosmic Noise Absorption (SCNA) on October 13, 1958. â C a l c u l a t e d 4 Time, MinuteB 1*0 100 seconds 3.0 X 10"Ì sec"''' = 50 s e c o n d s 6 Observed,'March 29, 1958, 13^2 U T Figure 26. Sudden Cosmic Noise Absorption (SCNA) on March 29, 1958. 743 V 6
INTERDISCIPLINARY RESEARCH Project 22.3 - Solar Flare Studies 1. Objectives. This work a t the McMath-Hulbert Observatory, U n i v e r s i t y of Michigan, was established to study world-wide f l a r e data f o r the IGY, systematize i t i n terms of r e p o r t i n g techniques, s t a t i s t i c s of occurrence, e t c . and to i n v e s t i g a t e the r e l a - tionships between f l a r e occurrence and geophysical events. The study included i n v e s t i - gations such as: a. Center-to-limb v a r i a t i o n s i n frequency, H-alpha i n t e n s i t y and w i d t h , ionospheric e f f e c t s , e t c . b. Radio frequency emission a t the time of f l a r e s . c. Age and magnetic properties of spots and plages w i t h varying numbers of f l a r e s . d. D i s t r i b u t i o n m Universal Time of f l a r e s , imp.>1. 2. Personnel. Dr. Helen Dodson Prince was the p r i n c i p a l i n v e s t i g a t o r . Miss E. Ruth Hedeman p a r t i c i p a t e d i n a l l aspects of the program, and student as s i s t a n t s aided i n the preparation of the data. 3. Results. Before study of f l a r e s during the IGY could be undertaken, i t was necessary to prepare a t a b u l a t i o n of f l a r e events from the l i s t of i n d i v i d u a l reports of f l a r e s i n the Quarterly B u l l e t i n of Solar A c t i v i t y . Such a l i s t was prepared and subsequently published by Solar A c t i v i t y World Data Center A as the "McMath-Hulbert Observatory Working L i s t of IGY Flares." I n a d d i t i o n a f l a r e index, approximately p r o p o r t i o n a l to the area of the f l a r e s , was determined f o r each day of the IGY. Be- cause of the apparent need f o r f l a r e data i n the above forms, s i m i l a r t a b u l a t i o n s f o r each of the four years 1959 to 1962 were prepared and published. These working l i s t s provided the basic f l a r e data f o r a l l of the analyses c a r r i e d out m t h i s p r o j e c t . The McMath-Hulbert Observatory Working L i s t s of Flares terminate w i t h 1962 because, a f t e r t h i s date, the Quarterly B u l l e t i n w i l l present f l a r e data i n the summarized or event form. I n order to f a c i l i t a t e comparison of o p t i c a l f l a r e data w i t h other manifestations of solar a c t i v i t y and w i t h possibly associated geophysical events, an a d d i t i o n a l , com- prehensive chronological catalogue was prepared w i t h the f o l l o w i n g primary e n t r i e s . A l l f l a r e s of importance_> 3; A l l SWF's of importance > A l l 10 cm events w i t h f l u x >500xl0-22watts/M2/cycle/sec.; A l l Type IV and Type I I radio-frequency events; A l l polar cap absorption events, A l l major geomagnetic storms, A l l "complex" sunspots ( p A . o r \ ) . For each of the primary e n t r i e s , the remaining or p e r t i n e n t f l a r e , ionospheric and radio-frequency data were included. This catalogue, prepared o r i g i n a l l y f o r the IGY, has been extended to cover 1957-1963 and i s c u r r e n t l y being prepared f o r p u b l i c a t i o n . The i n i t i a l survey of IGY f l a r e s revealed the existence of a gross inhomogeneity i n the basic f l a r e data. Approximately twice as many f l a r e s of importance'? 1 had been reported per hour from 05^ to 16^ UT as during the remainder of the Universal Day. Analysis of the data indicated t h a t c e r t a i n s t a t i o n s observing between 05^ and 16^ UT had reported, as, f l a r e s of importance "^ 1 , a large number of events t h a t observers during the other hours of the day would have c l a s s i f i e d as subflares. A systematic 744
INTERDISCIPLINARY RESEARCH e f f e c t of t h i s type continues i n world-wide f l a r e data through 1962 and necessitates special care i n the c o r r e l a t i o n of o p t i c a l f l a r e data w i t h other phenomena. A l l confirmed shortwave fades i n the summarizing tables of CRPL of NGS f o r the months of the IGY were compared w i t h concomitant solar a c t i v i t y . Of the 1,126 SWF's, 88%, or 994, occurred i n s u i t a b l e time-association w i t h known f l a r e s or subflares. For another 56 cases there are reports of concomitant 10 cm bursts or s i g n i f i c a n t limb or disk a c t i v i t y not s p e c i f i c a l l y c a l l e d f l a r e s . Systematic e f f e c t s existed i n the CRPL l i s t s of world-wide shortwave fades, both during the IGY and i n subsequent years. The nimiber of conformed shortwave fades reaches a maximum between 13^ and 19^ UT and drops to a deep minimum, 21^ to 23h ux. The de- pendence of both f l a r e and ionospheric data on Universal Time makes simple comparison of world-wide data f o r these two phenomena u n r e l i a b l e . T o t a l world-wide f l a r e and ionospheric data during the IGY in d i c a t e t h a t only 10% to 15% of the f l a r e s of impor- tance ^1 were accompanied by ionospheric disturbances. However, f o r i n t e r v a l s w i t h s e n s i t i v e ionospheric monitoring, shortwave fades were recorded w i t h 46% of the f l a r e s (imp, >1), The o p t i c a l , ionospheric and radio-frequency c h a r a c t e r i s t i c s of a l l f l a r e s assoc- i a t e d w i t h polar cap absorption, IGY t o 1962, were studied against the background of the magnitude of the proton events. S i m i l a r l y the c h a r a c t e r i s t i c s of f l a r e s probably associated w i t h severe, sporadic geomagnetic storms were i n v e s t i g a t e d . Important Ha f l a r e s covering or very near major spot umbrae and accompanied by strong continuum emission and radio frequencies, appear to be the solar events most frequ e n t l y associated w i t h these geophysical phenomena. The age of the plage i n which a f l a r e occurs seems to bear some r e l a t i o n to the detection of PCA on the earth. From 1957 to 1961, only one known PCA event was associated w i t h a f l a r e i n a plage i n i t s f i r s t r o t a t i o n . Series of spectroheliograms mad| by systematic changes of wavelength from 3 A on one side of the HD: or K l i n e s to 3 A on the other, have provided a vast c o l l e c t i o n of observational data r e l a t i n g to f l a r e s and associated a c t i v i t y . These records are c u r r e n t l y being examined and have already i n d i c a t e d that the great systems of loop-type prominences develop i n the postmaximum phase of f l a r e s w i t h strong, long-enduring Type IV r a d i a t i o n , and that the winking of filaments at the time of c e r t a i n f l a r e s stems from Doppler s h i f t s f i r s t to the redward and then to the v i o l e t of l i n e center, w i t h d u r a t i o n of about four minutes m each case, and subject to r e p e t i t i o n . Evidence i n - creases f o r a close association between a c t i v e filaments and the onsets of f l a r e s , 4, Bibliography, Helen w. Dodson and E. Ruth Hedeman. "Survey of Number of Solar Flares Observed During the I n t e r n a t i o n a l Geophysical Year," Journal of Geophysical Research, v o l . 65, 1960, pp. 123-31, Helen W. Dodson and E. Ruth Hedeman "Flares of July 16, 1959," Astronomical Journal, v o l , 65, 1960, p. 51. Helen W. Dodson and E. Ruth Hedeman. "Survey of Number of Flares Observed During the IGY." Astronomical Journal, v o l . 65, 1960, p. 51. Helen W. Dodson and E. Ruth Hedeman: "McMath-Hulbert Observatory Working L i s t of IGY Flares." IGY Solar A c t i v i t y Report Series No, 12, 1960, Helen W. Dodson and E. Ruth Hedeman. "Flare Index f o r Each Day of IGY." IGY Solar A c t i v i t y Report Series No. 14, 1961. 745
INTERDISCIPLINARY RESEARCH Helen W. Dodson and E. Ruth Hedeman: "McMath-Hulbert Observatory Working L i s t of Flares and Da i l y Flare Index f o r IGC - 1959." IGY Solar A c t i v i t y Report Series No. 15, 1961. Helen W, Dodson and E. Ruth Hedeman: "Observation of Loop-type Prominences i n Pr o j e c t i o n Against the Disk a t the Time of Certain Solar Flares." Proceedings of National Academy of Sciences, v o l . 47, 1961, p. 901. Helen W. Dodson and E. Ruth Hedeman: "Photographic Observations of Certain Flares Associated w i t h Polar Cap Absorption." A r k i v f o r Geofysik. v o l . 3, 1961, p. 469. Helen W. Dodson and E. Ruth Hedeman. "McMath-Hulbert Observatory Working L i s t of Flares and Daily Index f o r 1960." IGY Solar A c t i v i t y Report Series No. 18, 1962. Helen W. Dodson and E. Ruth Hedeman: "McMath-Hulbert Observatory Working L i s t of Flares and Daily Flare Index f o r 1961." IGY Solar A c t i v i t y Report Series No. 21, 1963. Helen W. Dodson and E. Ruth Hedeman- "Studies of Flares Associated w i t h Polar Cap Absorption." Astronomical Journal, v o l . 68, 1963, p. 290. Helen W. Dodson and E. Ruth Hedeman "Problems of D i f f e r e n t i a t i o n of Flares w i t h Respect to Geophysical E f f e c t s . " 10th Report on S o l a r - T e r r e s t r i a l Relations of the Inter-Union Commission on Solar and T e r r e s t r i a l Relationships, 1964. Helen W. Dodson and E. Ruth Hedeman "McMath-Hulbert Observatory Working L i s t of Flares and Daily Flare Index f o r 1962." IGY Solar A c t i v i t y Report Series No. 25, 1964. Helen W, Dodson- "C h a r a c t e r i s t i c s of Flares Associated w i t h Polar Cap Absorption." Transactions of the I n t e r n a t i o n a l Astronomical Union, v o l . XIB, (Proceedings, 1961), p, 474. 746
INTERDISCIPLINARY RESEARCH Project 22.4 - Study of Flare Spectra 1. Objectives. This p r o j e c t a t the McMath-Hulbert Observatory, U n i v e r s i t y of Michigan, was undertaken to secure and study spectra of f l a r e s recorded a t the observatory during the IGY and i n subsequent years. The observational records include the f o l l o w i n g : a. Low dispersion spectra from 7000 to 3600 A made w i t h a Wadsworth-type spectrograph; b. High d i s p e r s i o n , high r e s o l u t i o n spectra of selected wavelength regions made w i t h the vacuum spectrograph a t the McMath-Hulbert Observatory, 2. Personnel. Dr. Orren Mohler was the p r i n c i p a l i n v e s t i g a t o r and Dr. R. Teske, Dr. G. E l s t e , and Mr. R. Jayanthan were also associated w i t h the work. 3. Results. More than 250 spectra of f l a r e s , covering the wavelength range from the redward of Ha to beyond the l i m i t of the Balmer s e r i e s , were secured i n the summer of 1958. The spectra provide data f o r 112 d i f f e r e n t f l a r e s . I t i s of i n t e r e s t t h a t i n the e n t i r e s e r i e s , there are only two f l a r e s w i t h the ex c e p t i o n a l l y wide emission l i n e s so frequen t l y mentioned as c h a r a c t e r i s t i c of f l a r e s . These were the f l a r e s of 1958 July 30d i5h 23ra ur (imp. 2) and 1958 August 7<^ 14h 57in UT (imp. 3 ) . Both of these f l a r e s were r e l a t i v e l y close to the solar limb a t S 13° W 64° and S 16° E 71°, r e s p e c t i v e l y . Both f l a r e s were accompanied by severe ionospheric disturbances but are not known to have been associated w i t h any unusual geophysical e f f e c t s . The observational program included a v i s u a l search f o r the p o r t i o n of the f l a r e w i t h the b r i g h t e s t , widest emission so th a t the absence of ex c e p t i o n a l l y wide emission does not stem from mere misfortune i n placement of spectrograph s l i t . For some of the f l a r e s spectra were not secured during the f l a s h phase or maximum, but f o r others, spectra cover the f u l l development of the f l a r e . The most complete coverage was obtained f o r the f l a r e , importance 3, on 1958 August 22^ 14^ 28⢠UT. This f l a r e (N 18° W 10°) was accompanied by strong long-duration Type IV emission a t radio frequencies and was followed by a severe proton event and geomagnetic storm. This f l a r e , near the c e n t r a l p a r t of the solar d i s k , rose to maximum i n t e n s i t y r e l a - t i v e l y slowly and there i s no obvious evidence f o r the occurrence of unusually wide emission on any of the many spectra secured during a l l phases of the f l a r e . These low dispersion f l a r e spectra have been examined and measured by several i n v e s t i g a t o r s but the f i n d i n g s do not lend themselves r e a d i l y to physical i n t e r p r e t a - t i o n . Study of the spectra continues, i n the hope th a t progress can be made i n the physical i n t e r p r e t a t i o n of the f l a r e phenomenon. When f e a s i b l e , the vacuum spectrograph of the McGregor solar tower was used to obtain high d i s p e r s i o n , high r e s o l u t i o n records of chosen portions of the spectrum of f l a r e s . Most of the spectra were centered on Ha!, Hp, K, D i , D2, D3 or the magnesium t r i p l e t a t X, 5173, More than 200 such spectra were secured. A l l have been studied and photometrically traced by the densitometer. Because of the special i n t e r e s t i n the great cosmic ray f l a r e (imp. 3+) of 1960 November 12<1 13^ 15" spectra secured during t h i s f l a r e were chosen f o r special reduc- t i o n . Even though t h i s f l a r e was associated w i t h unusually intense i o n i z i n g r a d i a t i o n and exceptionally energetic p a r t i c l e - e m i s s i o n , the Ha emission f a i l e d to depart i n any important way from values of Ha w i d t h and c e n t r a l i n t e n s i t y , e x c i t a t i o n temperature, o p t i c a l thickness, and r a t e of r a d i a t i o n i n the Ha l i n e t h a t have been found f o r other f l a r e s of importance 3+. 4. Bibliography. Richard G. Teske: "The Ha Line i n the Flare of November 12, 1960." Astrophysical Journal, v o l . 136, 1962, pp, 534-545, 747
INTERDISCIPLINARY RESEARCH Project 22.5 - V a r i a t i o n of Cosmic Rays i n the Polar Regions 1. Objectives. This work undertaken a t the U n i v e r s i t y of Maryland provided f o r analysis of meson telescope data from the two Un i v e r s i t y of Maryland s t a t i o n s -- Thule, Greenland, and Wilkes S t a t i o n , A n t a r c t i c a . The several aspects of cosmic-ray v a r i a t i o n s i n v e s t i g a t e d were: a. solar d a i l y v a r i a t i o n , b. cosmic-ray storms or For- bush decreases, c. solar f l a r e increases, and d. the annual v a r i a t i o n . 2. Personnel. W. Webber was the p r i n c i p a l i n v e s t i g a t o r and V.L. Patel was also associated w i t h t h i s p r o j e c t . 3. Results. Several aspects of time v a r i a t i o n s of primary cosmic r a d i a t i o n were i n - vestigated using continuously recorded data a t Thule ( \ =88° N) and Wilkes ( X =76° S). They are as f o l l o w s : a. Solar Flare E f f e c t s on Cosmic Rays. We were p a r t i c u l a r l y i n t e r e s t e d i n e f f e c t s of small solar f l a r e s . The analysis of cosmic ray i n t e n s i t y by method of superposition was c a r r i e d out to get s t a t i s t i c a l l y s i g n i f i c a n t r e s u l t s . The increase obtained was 0.2% a t Thule and 0.4% a t Wilkes f o r f l a r e s i n c l u d i n g importance 2 (Maeda, P a t e l , 1961). This supports previous observations by Corrigan, Singer, and Swetnick (1958) t h a t even small f l a r e s can produce cosmic rays. Several i m p l i c a t i o n s on d i f f e r e n t models f o r production of solar f l a r e cosmic rays and t h e i r propagation through i n t e r p l a n e t a r y space were examined. Our i n t e r e s t i n cosmic ray increases during large f l a r e s also continued. Such increases occurred on May 4, 1960 (Maeda, P a t e l , Singer, 1961) and November 1960 (Maeda, P a t e l , Singer, 1961). They were observed also a t our mountain recording s t a t i o n s a t Banff and Climax. b. Seasonal V a r i a t i o n s . Due to the unique l o c a t i o n of our polar s t a t i o n s , Thule and Wilkes, i t was thought t h a t some important information on seasonal v a r i a t i o n s could be obtained. Our primary aim was to see i f there i s any c o n t r i b u t i o n from e x t r a - t e r r e s t r i a l sources i n such v a r i a t i o n . The seasonal v a r i a t i o n of meson i n t e n s i t y a t Thule and Wilkes was ~5% ( P a t e l , Maeda, 1960). The main problem was to eliminate any atmospheric c o n t r i b u t i o n w i t h good accuracy. This was done by using neutron data a t Thule ( P a t e l , Maeda, 1961). I t was also found t h a t most of t h i s seasonal v a r i a t i o n can be accounted by atmospheric e f - f e c t s , yet a small e x t r a - t e r r e s t r i a l c o n t r i b u t i o n cannot be excluded (Maeda, P a t e l , 1961). As a by-product of t h i s study, i t was discovered t h a t temperature c o e f f i c i e n t s i n the polar region are very high (~8.3%/km) compared to other places on the globe. An explanation f o r t h i s was given (Maeda, Pa t e l , 1961). Another important r e s u l t was the conclusion t h a t a constant r a t i o between neutron and meson i n t e n s i t y changes during Forbush decreases can be obtained i f meson data are accurately corrected f o r temperature. At Thule, i t was shown t h a t the de- creases are always 20% larger i n the neutron i n t e n s i t y . This constant r a t i o i s a sure t e s t of the correctness of the temperature c o e f f i c i e n t ; hence atmospheric e f f e c t s can be evaluated very accurately. c. Short-time V a r i a t i o n s . I n order to see i f v a r i a t i o n s i n cosmic rays occur during a few minutes time-scale, continuous records on the tape from high counting ra t e equipment i n s t a l l e d a t Climax, Colorado, were analyzed. I t was found t h a t v a r i a t i o n s occurring i n periods of f i v e minutes have a strong l o c a l time dependence (Pa t e l , Maeda, 1961). 748
INTERDISCIPLINARY RESEARCH 4. Bibliography, S.F. Singer: "Cosmic Ray Studies During the IGY." Am,Peoples Encyclopedia Yearbook, Events of 1956. J.J. Corrigan, S.F. Singer, amd M.J. Swetnick: "Cosmic Ray Increases Produced by Small Solar Flares." Phys, Rev. L e t t e r s 1, 1958, pp. 104-105, S,F, Singer: "A Model f o r Solar Flare Increases of Cosmic Rays Based on Hydro- magnetic Turbulence," Nuovo Cimento 8, Series X, (1958), pp. 197-201. V.L. Patel and K. Maeda. "Seasonal V a r i a t i o n of Cosmic Rays i n Polar Regions." B u l l , Am, Phys, Soc 5, (1960), 23. K. Maeda and V.L. Patel. "A Note on Solar Flare Cosmic Rays." J. Geophys. Research 66, 1961, pp. 1288-1289. K. Maeda and V.L. P a t e l : "Seasonal V a r i a t i o n s of Cosmic Rays i n Polar Regions." J. Geophys, Research 66, 1961, pp. 1389-1393. K. Maeda, V.L. P a t e l , and S.F. Singer: "Solar Flare Cosmic Ray Event of May 4, 1960." J. Geophys. Research 66, 1961, pp. 1569-1572. V.L. Patel and K. Maeda: "On the Short-time F l u c t u a t i o n of Cosmic Rays," B u l l , Am, Phys, Soc, 6, (1961), 52. V.L, Patel and K. Maeda: "Short-term Variations m Meson and Nucleon Component of Cosmic Rays," J, Geophys. Res. 66, (1961), pp. 1286-87, 749
INTERDISCIPLINARY RESEARCH Project 22.6 - Analysis of IGY Data from Alaska 1. Objectives. This p r o j e c t provided f o r broad i n t e r d i s c i p l a n a r y studies and analyses of Alaskan IGY data. P r i n c i p a l areas of study included the r e l a t i o n of a u r o r a l and solar a c t i v i t y , making use of analyses of o p t i c a l data i n the form of a l l - s k y camera observations and spectroscopic and photometric observations of auroras, and employing analyses of ionospheric absorption data and a u r o r a l radar information. This work thus integrated IGY data obtained p r i m a r i l y from s i x a u r o r a l radar s t a t i o n s (IGY Project 1,14) and a chain of s i x cosmic noise absorption measuring s t a t i o s (IGY Projects 1,43 and 6.20) i n Alaska i n t o the la r g e r body of IGY information. Data was also used from seven other cosmic noise absorption s t a t i o n s operating i n Canada, Greenland, Sweden, and the United States. Emphasis was placed on the i n t e r p r e t a t i o n of the data from each d i s c i p l i n e from two viewpoints: one, from that of s t a t i s t i c a l analysis and, two, from t h a t of analysis of disturbance-time v a r i a t i o n s . I n the l a t t e r , selected periods were chosen f o r the i n t e r d i s c i p l i n a r y studies - as f o r example - the period during the red a u r o r a l d i s p l a y of February 10-11, 1958. By t h i s technique a few of the most i n t e r e s t i n g periods were analyzed f i r s t , the r e s u l t s of which pointed the way to f u t u r e studies. 2. Personnel. C.T. Elvey was the p r o j e c t d i r e c t o r and c o n t r i b u t i o n s were made by the senior research s t a f f of the I n s t i t u t e : S-I Akasofu, A l b e r t Belon, Sydney Chapman, K.C. Clark, T.N, Davis, C,S. Deehr, L. Herman, V.P. Hessler, Harold Leinbach, R.S. Leo- nard, G.C. Reid, Masachita Suriura, Manfred Rees, Gian Rumi, G.J. Roraick. 3. Results. A great number of i n v e s t i g a t i o n s and researches were undertaken i n con- nection w i t h t h i s p r o j e c t , some of them continued under other support. I t i s not possible here to give i n d e t a i l a l l the conclusions, inferences and r e l a t i o n s h i p s r e - s u l t i n g ; below i s a summary of some of the work selected more-or-less a t random t o give a representative account of the research. From studies of the incidence near the a u r o r a l zone of a u r o r a l forms and t h e i r n o r t h and south motions, Davis found t h a t during the observing season 1957-58 the peak of the average a u r o r a l zone occurred a t 66-67° geomagnetic l a t i t u d e . Although the southern ex- t e n t of auroras r e t r e a t s northward a f t e r l o c a l magnetic midnight, the southward motion of the i n d i v i d u a l forms, observed a t the southern edge of the a u r o r a l zone, predominates o v e r t h e northward motion throughout most of the n i g h t . The data i n d i c a t e the existence on any given ni g h t of a l a t i t u d e p o s i t i o n near which many a u r o r a l f o r m s o c c u r . The f i r s t motion of auroras i n c i d e n t n o r t h of t h i s p o s i t i o n tends to be northward, and the f i r s t motion of auroras i n c i d e n t south of t h i s p o s i t i o n tends to be southward, A curve showing the occurrence of a u r o r a l forms peaks a t , and i s nearly symmetrical about, l o c a l geographic midnight, but the i n t e n s i t y of a u r o r a l emissions measured over the c e l e s t i a l hemisphere remains a t a high l e v e l a f t e r midnight. Study of the data from other loca- t i o n s , however, revealed t h a t two maximum, one major a t 07 h l o c a l time and one minor near 19 h occurred, f o r example, a t Resolute Bay, where the forms were generally less w e l l developed and less numerous than i n the a u r o r a l zone. The alignment of arcs a t Resolute Bay, Thule, and A l e r t f i t s a model centered near the geomagnetic pole and f i x e d w i t h respect to the sun. The patterns of a u r o r a l form alignment i s s i m i l a r to Chapman's ide a l i z e d SD current system; the patterns are not suggestive of a c i r c u l a r or s p i r a l inner a u r o r a l zone. Auroral spectrograms taken w i t h the IGY p a t r o l spectrograph a t College, Alaska, during the great aurora of 10-11 February 1958 were studied by Clark and Belon. The spectrograms showed high v i b r a t i o n a l e x c i t a t i o n i n the B? sta t e of NJ, as i n d i - cated by the enhanced i n t e n s i t i e s of the 4652A (1,3) and 4600A (2,4) bands r e l a t i v e t o the 4709A (0,2) band of the f i r s t negative system. The g r a t i n g spectrograms consisted of 18 successive exposures throughout the n i g h t from 0308 to 1559 UT 11 February and 750
INTERDISCIPLINARY RESEARCH resolved the magnetic meridian from north to south along the length of the s i l t image. Intensity ratios were compared with those of synthetic spectra at the same 8A resolution calculated assuming Boltzman distributions at various excitation temperatures of vibra- tion and rotation. The excitation can i n this manner be roughly characterized by T (vib) = 4000°K and T (rot) = 2500°K. The enhancement was frequently so strong as to reverse the normally decreasing order of intensities of the (0,2) and (1,3) bands. Unusually Intense emission from hydrogen was frequently present, and the measured Doppler sh i f t s of H indicated velocities up to at least 800 km/sec. These auroral measurements lend observational support to the concept that charge exchange becomes a major process i n great auroras. In addition, a large number of rare atomic lines were seen. Most of these enhanced emissions were Identified as transitions of 01 and N i l . In particular, the i d e n t i f i c a t i o n of both low level forbidden lines of N i l at 5755k and d e f i n i t e l y established their presence i n the auroral spectrum. This great aurora had several unusual features, such as (1) the generally high altitude and d i f - fuseness of the display, (11) the presence of hydrogen i n great abundance and of possibly slower maximum speed than usual, ( i l l ) a general enhancement of the nebular atomic lines, and ( i v ) high vibration i n the state of Nj. I t i s speculated that these features can perhaps be explained by Increased Importance of charge exchange be- tween slow incoming protons and neutral nitrogen molecules over direct ionization and excitation of N2 by fast protons and electrons, and that the known large f l u x of low energy hydrogen atoms may have been very effective i n exciting the atomic states of forbidden m u l t i p l i c i t i e s through spin exchange collisions. The IGY rlometer program showed that measurement of ionospheric absorption i n the Arctic i s a sensitive method of detecting low energy cosmic rays of solar origin. Reld and Lelnbach, i n a study of some 24 events, note an apparent assymmetry i n the di s t r i b u t i o n of cosmic-ray producing flares across the solar disk and a pronounced degree of uniformity i n the d i s t r i b u t i o n of the radio wave absorption over the terres- t r i a l polar cap. The former can be considered as supporting the hypothesis of the outward extension of a solar magnetic f i e l d by low-velocity charged particles traveling r a d i a l l y outward from the sun. The l a t t e r may be explained either by a sharp flattening in the particle energy spectrum below the energy corresponding to a Stormer cutoff at 70° geomagnetic latitude, or by the confinement of the magnetic f i e l d within a f i n i t e region as a result of the Impact of the streams of low energy particles responsible for setting up the interplanetary magnetic f i e l d . Analysis of data collected by fiv e auroral radars located i n Alaska showed the di s t r i b u t i o n of ionospheric disturbances as a function of time and location. An ap- parent radar auroral zone with a maximum at 67° geomagnetic latitude was found by Leonard i n this study. The decrease i n occurrence to the south of this maximum is v e r i f i e d , but the decrease to the north cannot be accurately defined, as the r o l l of aspect s e n s i t i v i t y is not f u l l y understood. The radar auroral zone spreads to the south during increased magnetic disturbance, and some indication i s found of a lessening of a c t i v i t y well north of the visual auroral zone. A conclusion i s also reached that the layer causing radio wave absorption during aurora i s not uniform but contains "holes" or regions of low absorption. The diurnal occurrence curves Indicate two prin- cipal maxima. One is observed at a l l stations at times near local midnight. The time of the other maximxjm depends on the latitude of observation - i t i s later i n the morning at the more northern locations. These two echoes exhibit d i f f e r i n g degrees of aspect s e n s i t i v i t y , the morning echoes having a narrower-scattering polar diagram. A study of IGY magnetic and aurora data, and a consideration of the various extent theories led Akasofu and Chapman to work out a detailed theory of magnetic storms and a line discharge theory of the aurora. I t i s shown that under the influence of the solar wind, the earth's f i e l d can be reversed i n limited regions when the ring current is appreciably enhanced. This involved the formation of neutral lines one of which is postulated to be the source of the particles that can produce the aurora. Several predictions are made as to the character of the magnetic f i e l d i n space that can be confirmed by accurate magnetic observations on space probes. 751
INTERDISCIPLINARY RESEARCH The last two international cooperations, the F i r s t and Second Polar Years, advanced greatly our knowledge of the aurora. The IGY all-sky camera network provided, however, a far more systematic data towards understanding of the auroral morphology. One of the most important aims of this great network was to study simultaneously an auroral display over the whole polar sky within an accuracy of one minute. Such an analysis of the data thus accumulated at the WDC-A has been carried out by Akasofu and Kimball, I t has been found that the aurora simultaneously shows various active features at different places over the whole polar regions. The break-up i s known to be the most violent form of display and i t i s seen most often around midnight. However, at the same time, or a l i t t l e l a t e r , quiet arcs m the evening sky may brighten or become folded. Also at the same time, i n the auroral cap encircled by the auroral zone, active bands move from the zone towards the geomagnetic pole. For such a sequence of auroral events over the entire polar region, the name "auroral substorm" i s suggested by Chapman. Each auroral substorm has a lifetime of order from one to three hours, and con- sists of two phases. I t always originates around the midnight meridian at the place where quiet arcs exist. The f i r s t phase is characterized by a sudden increase i n the brightness of the part of a quiet arc that is near the midnight meridian, and by sub- sequent rapid motion of the arc towards the geomagnetic pole. In the evening sector, this expansion is seen as a westward traveling surge and d r i f t i n g loops. This expan- sive phase is rapid, taking place within only about 10s30 minutes. After a certain lapse of time, such abrupt and violent a c t i v i t y affects the aurora i n various ways i n both the early evening and late morning sectors. When bands moving rapidly polewards a t t a i n their northernmost point ( i n the northern hemisphere), they begin to return to their o r i g i n a l location. This i s the beginning of the second or recovery phase. During this phase, various after-effects of the f i r s t expansive phase propagate towards both the evening and morning t w i l i g h t sectors. The second phase may last more than 2 hours, and i t s end there may be a few quiet arcs i n the region where the arcs were o r i g i n a l l y located before the substorm. Several such substorms may occur at intervals of a few hours or less during a moderately disturbed period coinciding with a magnetic storm or minor disturbance. In more complicated occurrences, a new substorm may start before the second phase of the preceding one is over. As the study i s based on IGY data, i t corresponds to a time of rather high magnetic a c t i v i t y , although not necessarily to a time when a d i s t i n c t sudden commencement storm i s i n progress. In fact, such substorms were almost daily events during the IGY. During sudden commencement magnetic storms, however, the frequency and the intensity of the auroral substorms increase considerably. 4. Bibliography. C. Reid and H. Leinbach: "Low Energy Cosmic-Ray Events Associated with Solar Flares." JGR. vol. 64, no. 11, 1959, pp. 1801-05 K.C. Clard and A.E. Belon: "Spectroscopic Observations of the Great Aurora of 10 February 1958 - I . Abnormal Vibration of Nj." J. Atm. Terr. Physics, vol. 16, 1959, pp. 205-19 A.E. Bacon and K.C. Clark: "Spectroscopic Observations of the Great Aurora of 10 February 1958 - I I . Unusual Atomic Features." J. Atm. Terr. Physics, v o l . 16 1959, pp. 220-27. Helen M. Tryon: "Auroral Index for College, Alaska, Derived from All-Sky Camera Photographs, Sept. 1957 - December 1958." U. Alaska, Geophys. Inst. Report R-97, Nov. 1959. 752
INTERDISCIPLINARY RESEARCH T.N. Davis: "Brief Descriptions of Auroral Displays over Alaska During 1957-58." U. Alaska, Geo. Inst. Report R-99, Jan. 1960. T.N. Davis and D.S. Kimball: "Incidence of Auroras and Their North-South Motions i n the Northern Auroral Zone." U. Alaska, Geo. Inst. Report R-lOO, Jan. 1960. T.N. Davis, C.S. Deehr, and H. Leinbach: "An Evaluation of Auroral All-Sky Camera Observations." U. Alaska, Geo. Inst. Report R-IO^), March 1960. D.S. Kimball. "A Study of the Aurora of 1959." U. Alaska, Geo. Inst. Report R-109, A p r i l 1960. T.N. Davis: "The Morphology of the Polar Aurora." JGR, v o l . 65, Oct. 1960, pp. 3497-3500. F. E. Roach and M.H. Rees: "The Absolute Zenith Intensity of [O I ] 5577 at College, Alaska." JGR, vol. 65, May 1960, pp. 1489-93. L. Herman: "Emission Spectrum of the Aurora at College, Alaska." Ann, de Geoph.. vol. 16, no. 3, 1960, pp. 304-18. M.H. Rees, A.E. Belon, and G.J. Romick: "The Systematic Behavior of Hydrogen Emission i n the Aurora, I . " Plan. & Space Sci., vol. 5, 1961, pp. 87-91. G. C. Reid and M.H. Rees: "The Systematic Behavior of Hydrogen Emission i n the Aurora, I I . " Plan. & Space Sci». vol.5, 1961, pp. 97-104. L. Herman and A.E. Belon: "Results of a Survey of IGY Patrol Spectra at College, Alaska." U. Alaska, Geoph. Inst. Report R-113, March 1961. R.S. Leonard: "Distribution of Radar Auroras over Alaska." U. Alaska, Geoph. Inst. Report R-116, A p r i l 1961. C.S. Deehr: "A Spectrophotometric Study of the Aurora of 27 November 1959 at College, Alaska." U. Alaska, Geoph. Inst. Report R-119, May 1961, Plan. & Space Sci.. vol. 8, 1961, pp. 49-58. S.I. Akasofu and S. Chapman: "A Neutral Line Discharge Theory of the Aurora Polaris." Phil. Trans, Roy. Soc.. A., v o l . 253, A p r i l 27, 1961, pp. 359-406. S.I. Akasofu and S. Chapman: "A Study of Magnetic Storms and Auroras." U. Alaska, Geoph. Inst. Report, March 1961. S.I. Akasofu and S. Chapman: "A New Theory of the Aurora Polaris." Am. Rocket Soc. vol. 31, June 1961, pp. 775-83. S.I. Akasofu: "The Dynamical Morphology of the Aurora Polaris." JGR, vol. 68, March 1963, pp. 1667-73. S.I. Askasofu: "The Dynamical Morphology of the Aurora Polaris." Ann. IGY. vol. XX, Part I I I , 1963, pp. 331-64. S.I. Akasofu: "Large Scale Auroral Motions and Polar Magnetic Disturbances." I.J. Atmosph. Terr. Phys. 19, 10-25 (1960). S.I. Akasofu and S. Chapman: "A New Theory of the Aurora Polaris." Am. Rocket Soc. 31, 1961, pp. 775-83. 753
INTERDISCIPLINARY RESEARCH S.I. Akasofu: "Large-scale Auroral Motions and Polar Magnetic Disturbances^ I I . The Changing Distribution of the Aurora During Large Magnetic Storms." J. Atmosph. Terr. Phys.. 24, 1962, pp. 723-727. S.I. Akasofu and S. Chapman: "Large-scale Auroral Motions and Polar Magnetic Disturbances, I I I . The Aurora and Magnetic Storm of 11 Feb. 1958, J. Atmosph. Terr. Phys.. 24, 1962, pp. 785-96. S.I. Akasofu and S. Chainnan: "A Large Change In the Distribution of the Aurora During the 11 Feb. 1958 Magnetic Storm." J. Atmosph. Terr. Phys.. 24, 1962, pp. 740-42. S.I. Akasofu and S. Chapman: "The Ring Current and a Neutral Line Discharge Theory of the Aurora Polaris." J. Phys. Soc. Japan, 17, Supple. A-I, 1962. S.I. Akasofu and S. Chapman: "The Lower Limit of Latitude (U.S. Sector) of Northern Quiet Auroral Arcs, and I t s Relation to D8t.(H)." J. Atmosph. Terr. Phys.. 25, 1963, pp. 9-12. S.I. Akasofu and S. Chapman: "The Aurora, IGY/C Symposium, Proc. Nat. Acad. Sci. S.I. Akasofu and D.S. Kimball: "The Dynamics of the Aurora, I . I n s t a b i l i t i e s of the Aurora." J. Atmosph. Terr. Phys. (In press.) S.I. Akasofu: "The Development of the Auroral Substorm." Plan. & Space Sci. (In press.) T.N. Davis and D.S. Kimball: "The Auroral Display of February 13-14, 1958." U. Alaska, Geo. Inst. Report R-120, Jan. 1962. T.N. Davis: "The Morphology of the Auroral Displays of 1957-1958." JCR. vol. 67, Jan. 1962, pp. 59-110. T.N. Davis: "Negative Correlation Between Polar-Cap Visual Aurora and Magnetic A c t i v i t y . " JGR. vol. 68, Aug. 1963, pp. 4447-4453. T.N. Davis and R.N. DeWltt: "Twenty-four-hour Observations of Aurora at the Southern Auroral Zone." JGR. vol. 68, 1963, pp. 6237-6241. R.N. DeHitt: "The Occurrence of Aurora i n Geomagnetically Conjugate Areas." JGR, v o l . 67, A p r i l 1962, pp. 1347-1352. 754
INTERDISCIPLINARY RESEARCH Project 22.7 - Theoretical Studies of Upper Atmosphere Data 1. Objectives. This project at the Central Radio Propagation Laboratory, National Bureau of Standards, was a complement to the various operational projects i n ionospheric physics and airglow carried out at CRPL during the IGY, i n order to permit f u l l e r study of the data and especially to explore interdisciplinary relation- ships i n certain phenomena of the upper atmosphere. I t was also intended to look at data from other IGY investigations. I.e., geomagnetism, and to consider data from the world-wide e f f o r t available through the IGY World Data Centers. 2. Personnel. Senior scientists associated with this project were K.W. Bowles, R.S. Cohen, W. Q. Crichlow, R. W. Knecht, C.G. R l t t l e , F.E. Roach, A. H. Shapley, R.J. Slutz, E.K. Smith; other investigators at the Laboratory also contributed to these investigations, as indicated below i n the bibliography. 3. Results. Since the work undertaken here is i n many ways a continuation of the individual operational projects at CRPL, i t i s d i f f i c u l t to distinguish between the results based on this project and on the operational projects. Much of the l a t t e r i s summarized under individual projects carried out by CRPL, the results cited below, represent a sampling of the f u l l results as reflected i n the bibliographies under this and the operational projects. From the times of occurrence of spread F at Talara, Chiclayo, Chimote and Huancayo, Peru, Knecht noted that, particularly for short-lived spread F, such observations may be used to compute average d r i f t s . With the caution that since the stations l i e approximately i n a straight li n e and therefore such derivation of d r i f t velocities i s not unambiguous, but noting that other work has shown that north- south d r i f t i s usually small, Knecht found average velocities of 135 m/sec towards the east, i n agreement with d r i f t s found i n Africa during the same period. In another investigation, Knecht examined (foEo extrapolated to zero zenith angle) for Puerto Rico and Maul, s a t e l l i t e acceleration as derived from prevision o r b i t a l computations, dally solar radio flux at 2800 Mc, daily Integrated intensity of the solar coronal green line emission, and the dally flare index. I t was con- cluded that (1) (FoEo)shows a close day-to-day correlation with the 2800 Mc flu x , ( i i ) the s a t e l l i t e accelearatlon i s the most closely associated with the 2800 Mc flux , and ( i l l ) the maximum of the preliminary fla r e index show a suggestively close coincidence with the maxima of the s a t e l l i t e acceleration and the 2800 Mc fl u x . Using lonographs from the close-spaced equatorial network of ionosondes, Knecht analysed the occurrence of equatorial sporadic E, which occurs regularly during the daylight hours i n a narrow belt close to the magnetic dip equator. A regular dis- t r i b u t i o n curve was found, symmetric with respect to the dip equator, with a "half- power" width of about 11°, or 700 km. This agrees with Forbush's figure of about 600 km derived from magnetic data. From analysis of the forward scatter propagation of 50 Mc signals across the magnetic equator, Bowles and Cohen were able to study E-reglon i r r e g u l a r i t i e s of the equatorial ionosphere, and found that: a. These i r r e g u l a r i t i e s support strong obloque scatter propagation of 50 Mc/s radio waves during both the daltlme and nighttime. b. The i r r e g u l a r i t i e s are at a height of about 100 km, c. There is an asymmetry i n the scatter effects about the magnetic equator fZtV^^ inerldian, with i r r e g u l a r i t i e s of greater strength occurring to the 755
INTERDISCIPLINARY RESEARCH d. During a year of scatter observations, daytime blanketing sporadic-E i r r e g u l a r i t i e s occurred at latitudes to either side of the magnetic equator, but were not present i n i t s immediate v i c i n i t y . e. The equatorial sporadic-E configuration on equatorial lonograms is produced by i r r e g u l a r i t i e s i n the equatorial electrojet. f. The electrojet i r r e g u l a r i t i e s occur m a layer extending from about 100 to 107 km i n height, which bifurcates into two layers from time to time. g. Radio techniques for observing the electroject offer a possible means for resolving changes in this current into their charge and velocity constituents. h. The equatorial sporadic-E i r r e g u l a r i t i e s are plane waves fronts parallel to the magnetic lines of force, d r i f t i n g westward with wave normals at various angles i n the equatorial plane. 1. These i r r e g u l a r i t i e s are at least 200 meters i n length, measured along the magnetic f i e l d lines, with at least one transverse dimension of the order of 6 meters or less. J. The concept of a " c r i t i c a l frequency" of equatorial sporadic-E has l i t t l e significance. h. The "equatorial slant sporadic'-E" configuration i s really another mani- festation of the "equatorial sporadic'-E" i r r e g u l a r i t i e s , and results from echoes in the equatorial plane. An examination was made of the global dis t r i b u t i o n of sporadic-E, based on data from the global network of lonosondes as well as the special sporadic E experiment conducted by scientists of CRPL during the IGY. Leighton, Shapley and Smith found that an earlier indication of a minimum over Siberia was m fact real and not ascirbable to lack of data. I t i s thought that the explanation l i e s i n the fact the maximum over Canada of Eg (and certain other auroral zone effects such as polar black- outs) i s related to the position of the magnetic pole â near Thule, Greenland. Comparison of Eg occurrence m 1954 and 1958 shows that there i s a very weak solar cycle effect, i t any at a l l , i n Eg. From the IGY data, eight types of Eg were recognized and codified, as follows: h -- (high, daytime only (common i n temperate latitudes) c -- (cusp), daytime only, (common i n temperate latitudes) 1 â (low), daytime only (common i n temperate latitudes) f â ( f l a t ) , night-time only a â (auroral) (common at auroral latitudes) r â (retardation) (common at auroral latitudes) q -- (equatorial) (common at low latitudes) s -- ( s l a n t ) , always seen i n association with another type (occurs both at low and auroral latitudes) 756
INTERDISCIPLINARY RESEARCH Study of diurnal and seasonal occurrence yielded the following behavior for ten stations: a. f-type at Thule, Ellsworth and the South Pole occurs mostly i n winter ( t h i s being night-time m these areas). b. 1-type proves to be largely a morning and evening type as one approaches the equator. c. h-type I S essentially confined to the lower latitudes of the temperate zones. d. a- and r-types are localized to the auroral zone. e. The mid-latitude summer maximum i n t o t a l sporadic E i s primarily due to c-type Eg. f. q-type i s restricted to the immediate v i c i n i t y of the magnetic equator and is a daytime, a l l year phenomenon. g. s-type occurs at the magnetic equator (similar time as q-type) and i n the auroral zone and polar cap. 4. Bibliography. K. L. Bowles, R. Cohen: "A Study of Radio Waves Scattering from Sporadic E near the Magnetic Equator," pp.51-77 H. I . Leighton, A. H. Shapley, E. K. Smith, Jr.: "The Occurrence of Sporadic E During the IGY," pp.166-77 S. C. Gladden: "A Note on the Heights of the Different IGY Types of Eg," pp.178-81 W. B. Chadwick: "Variations i n Frequency of Occurrence of Sporadic E, 1950-1950," pp. 182-93 R. W. Knecht, R. E. McDuffie: "On the Width of the Equatorial E Belt," pp.215-18 ^ K.Tao: "A Theoretical Study of Sporadic E Structure i n the Light of Radio Measurements," pp.253-57 (Above papers i n : "Ionospheric Sporadic-E" E.K. Smith, S. Matsushita (eds.) Pergumon Press, 1962) 757
INTERDISCIPLINARY RESEARCH Project 22.8 - Analysis of IGY Upper Atmosphere Data 1. Objectives. This project at the University of Colorado was planned to study IGY data from several disciplines with a view toward (a) more complete i d e n t i f i c a t i o n of radiations i n the solar X-ray and u l t r a v i o l e t spectra taken with rockets and to study relations to ionospheric photochemical processes; (b) analysis of airglow and high altitude meterological data to study the dynamics of airglow excitation and of move- ment; and (c) seeking the re l a t i o n between solar ionizing radiation and changes i n the ionized atmospheric regions. 2. Personnel. W. A. Rense was project director; E. Todd, Charlotte Pecker, F. Rohrllch, M. Mizushima, N. Milford, C. Varsovsky, D. Hunt, M. Rees and others con t r i - buted to the work. 3. Results. Pecker and Rohrllch collaborated on the i d e n t i f i c a t i o n of the solar UV emission lines observed by Rense and his associates using rocket-borne spectrometers. A systematic study of allowed transitions i n the region 1215 - 89 A resulted i n an extensive tabulation of such transitions for a l l atoms and ions m the Isoelectronlc sequences based on the two short periods Lithium through Argon. Based on t h i s tabulation, the large majority of observed UV emission lines were i d e n t i f i e d , with the additional use of intensities and other information available i n each particular case. A study was also carried out on forbidden transitions; a systematic study was made of the forbidden lines i n the isoelectronlc sequences of the short periods mentioned above. A l l of the lowest energy metastable configurations were considered, since a l l known coronal emission lines stem from them. Using theoretical as well as experimental information, a l l isoelectronlc sequences were extrapolated up to the ions that correspond to the highest coronal temperatures. Published i n Astrophysical Journal, Supplement No, 79, Vol. V I I I , pages 227-276, Nov. 1963. Mr. Douglas Hunt, a graduate student i n the physics department, worked up a model of the thermosphere, i n which he computed temperature variation with height i n a noon tropical atmosphere starting with the solution of the static temperature d i s t r i b u t i o n equation, which sets the sum of conductive and radiative heat loss rates equal to the rate of radiative heat gain. Hunt also considered the formation of the F-region, calculating ion density and temperature gradients i n that region. Published i n Journal of Geophysical Research Vol. 66, p. 1673-82 (1961), with T. E. Van Zandt. C, Varsavsky computed key atomic parameters. The nuclear-charge expansion method was used to compute electric dipole matrix elements for t r a n s i t on probabili- ty calculations of many UV lines of interest. Electron excitation cross sections ( t o t a l ) for optically permitted lines were also determined. The results, along with the theory and methods of calculation, were published i n the "Astrophysical Journal", Supplement No. 53, Vol. V I I , P. 75-108, March (1961). 758
INTERDISCIPLINARY RESEARCH Project 22.9 - Analysis of F Region Ionospheric Data 1. Objectives. This project at the Pennsylvania State University was undertaken to extend and continue the true height analysis program at PSU, f i l l i n g i n gaps where necessary, and making world-wide analyses for selected storms. The resulting data were to be used to examine the physical processes of electron-production, loss and transport, with a view toward constructing a theory of the Fl and F2 ionospheric regions. 2. Personnel. E. R. Schmerling was the principal investigator. R. Goldberg and S. Chandra were associated with the work and Miss A. Robbins, Ionosphere Research Station, Slough, England, was a guest worker for a short period. 3. Results. As simple parameters which characterize the height and thickness of the F region, Schmerling suggested the use of heights where the electron densities are fixed fractions of the maximum density, NÌ . Specifically, he suggested h(.9 ^ ) . and h(.5Nm). h(.9N(â) is s u f f i c i e n t l y close to hj, to give the same diurnal trend, but also s u f f i c i e n t l y low to remove measurement d i f f i c u l t i e s inherent i n hm. The quantity h(.9 N^) - h(.5 Ngj) can be used to characterize the lower semi-thickness of F2. These quantities were determined for a l l the quiet day data obtained under project 6.9 and the storm data obtained under this project. These data have been used by Somayajulu i n his work on magnetic storms. From the equation of continuity for free electrons, an expression was developed for the v e r t i c a l transport velocity that can be evaluated from electron density profiles subject to a knowledge of electron production and loss. No attempt was made i n this preliminary study to separate the transport term into diffusion and d r i f t contributions since the production and loss terms were not known to suff i c i e n t accuracy. Data from Huancayo and Talara, Peru, Canal Zone, and Washington, D. C, indicated that the velocity is predominantly downward during the night and upward during the day at equatorial stations. The v e r t i c a l velocity was found to be of the order 25 m/s, i n essential agreement with S data and dynamo theory. There were indications at Washington of an apparent phase reversal from summer to winter which could account for the fact that winter day electron densities are larger than summer day values. Times near sunrise were excluded from this analysis because of errors at low altitudes. Near sunrise, electron densities increase rapidly at a rate, , almost independent of a l t i t u d e . This rate shows significant variations with season and latitude. When compared with the noon value of cos X,where X i s the solar zenith angle, i t is found that these quantities are i n phase tor Huancayo and Talara (near the equator), out of phase for Washington, and somewhat indeterminate for the intermediate station, Panama. This result suggests the influence of electrodynamic forces near sunrise, since the noon solar zenith angle locates the position of the Sq current system which changes direction with l a t i t u d e . Electron density data from lonogram reduction were compared with those obtained by other methods. No significant discrepancies were discovered, and recommendations were made for further comparisons. The charge-transfer equations under photoequilibrium were investigated. I t was concluded that these were inadequate to account for the seasonal effects i n the F region without the introduction of other factors, such as variations of temperature and composition. I t I S well known that, near the magnetic equator, the contours of constant 759
INTERDISCIPLINARY RESEARCH electron density are displaced i n a characteristic way as a function of magnetic dip angle. This i s known as the geomagnetic anomaly. The part played by diffusion was examined at equinox noon, when the anomaly i s symmetrical about the dip equator, and quasi-equilibrium can be assumed. I t was found that the electron density height profiles are closely exponential below the F2 peak. The diffusion term in the continuity equation i s then found to be proportional to the electron density, N, and always positive, meaning that diffusion increases N below the peak by an amount which increases with dip angle, I . I t was shown that, at constant height, the variation of N with I I S approximately parabolic, and that the slopeof the N-I curve increases with height. I t was concluded that quite simple arguments based on diffusion could account for some of the most s t r i k i n g features of the geomagnetic anomaly, and that this anomaly i s more reasonably ascribed to an excess of ionization arising from diffusion at either side of the dip equator than to a deficiency of ionization at the equator. Following further the role of diffusion at the dip equator, two models were investigated: i n case 1, i t was assumed that the electron density i s constant along a f i e l d l i n e ; i n case 2, i t was assumed that there is diffusive equilibrium along a f i e l d l i n e . I t was found that case 1, although m better agreement below the F2 peak, i s not r e a l i s t i c since m r e a l i t y gravity cannot be neglected, and the deduc- tions above F2 peak do not conform with the limited data available. Case 2 appears to be more soundly based, even though i t does include assumptions concerning diffusive equilibrium that are not attained below the F2 peak. I t i s concluded that the observed values of N l i e between the l i m i t i n g cases of diffusive equilibrium and no diffusion. The effect of diffusion i s to d i s t o r t the contours of constant electron density and the distortion increases with altitude i n the manner expected from an increasing diffusion coefficient. Above the F2 peak, i t appears that the diffusive equilibrium d i s t r i b u t i o n i s followed quite closely, and this has been confirmed by the Alouette s a t e l l i t e . 4. Bibliography. E. R. Schmerling: "Height and Thickness Parameters for Region F of the Ionosphere," J.G.R., v o l . 65, pp. 1072-3, March 1960. S. Chandra, J. J. Gibbons, E. R. Schmerling: "Vertical Transport of Electrons m the F Region of the Ionosphere," J.G.R., vol. 65, pp. 1159-75, Apr i l 1960. E. R. Schmerling: "Effects of Vertical Diffusion of Electrons Near the Magnetic Equator." Nature, v o l . 188, pp. 133-4, Oct. 8, 1960. R. A. Goldberg, E. R. Schmerling: "The Distribution of Electrons near the Geomagnetic Equator," J.G.R., vo l . 67, pp. 3813-15, Sept. 1962, E. R. Schmerling: "A Test of the Charge-Transfer Hypothesis," NATO Conference Series, Vol, 2, Electron Density Profiles, pp. 304-310, 1962, Pergamon Press, Oxford. E. R. Schmerling: "Results of an IGY True Height Survey" Ionospheric Radio, pp. 17-20, 1962 Elsevier (Amsterdam). E. R. Schmerling: "Comparison of N(h) Profiles from lonogram Reduction with those obtained by Other Methods," Ionospheric Radio, pp. 21-24, 1962, Elsevier (Amsterdam). Y. V. Somayajulu: "Magnetic Storm Effects on the F Region of the Ionosphere" J. Geophys. Res., 65, pp. 893-895, (1960). 760
INTERDISCIPLINARY RESEARCH Y. V. Somayajulu: "Changes i n the F Region during Magnetic Storms," J. Geophys. Res., 68. PP. 1899-1922, (1963). Y. V. Somayajulu: "Evidence on the Horizontal Diffusion of F Region Ionization along the Magnetic Lines of Force i n Equatorial Latitudes," J. Geophys. Res., 69, 561-563, (1964). 761
INTERDISCIPLINARY RESEARCH Project 22.10 - Analysis of Ionospheric Backscatter Data 1. Objectives, This project at the Radio Science Laboratory, Stanford University, was designed to study the IGY data obtained by the network of backscatter sounders. Ionospheric backscatter soundings at oblique-incidence are especially valuable i n the study of two types of investigations. F i r s t , those investigations that require continuous large-region surveillance and second, those that by virtue of r e f l e c t i o n geometry are only observable at oblique incidence. In the f i r s t category are: a. The study of sporadic-E occurrence and the motion of sporadlc-E patches. b. The study of large-scale F-region t r a v e l l i n g disturbances. In the second group are: a. Studies of the aurora and the radio propagation phenomena associated with the aurora. b. Studies of field-aligned i r r e g u l a r i t i e s occurring at low and middle latitudes. c. Studies of ionospheric t i l t s and their influence on propagation over large distance without interverimg ground reflections. d. Studies of radio-reflections from meteor ionization t r a i l s . 2. Personnel. A. M. Peterson was project director and R. D. Egan was principal investigator. 3. Results. Auroral noise was observed on the backscatter records and an invest i - gation was undertaken, using sweep-frequency riometer data, to ascertain whether the noise was real or simply a transformation of anomolously propagated signals beyond the l i m i t of recognizable intelligence. I t was concluded that actual noise was being observed and mechanisms of noise generation were looked into; a study was also made of correlations between the observed noise and observations i n the trapped particle regions and magnetic storm conditions. I t was found that auroral noise does not correlate with daily magnetic indices although there i s a general overall storm-period correlation. The noise generally comes up strongly at the onset of the magnetic storm and then decays i n amplitude r e l a t i v e l y slowly over the next 10 to 15 nights, i n contrast with the magnetic a c t i v i t y , which may return to normal within a few days. A quite good hour-by-hour correlation was also observed between spread F and nighttime Eg, as observed by the lonosonde at Seattle, and the presence of noise on modified riometers, as well as with field-alighted irregular echoes observed with the Stanford backscatter sounder. The network of backscatter sounders made possible an investigation of effects of surface characteristics of the earth. For example, i t had been known for some years that E a c t i v i t y was far more prevelent to the west of Stanford ( i . e . , over water) than to the east and the question was raised as to whether there i s a systematic difference between Eg over land and water, or more generally, whether there might be differences over mountain regions and plains. I t was found that a 762
INTERDISCIPLINARY RESEARCH definite preference exists for Eg over mountains as compared with non-mountainous terr a i n , which cannot be explained by local site conditions ( i . e . , antenna screening). I t was also found that the ground backscatter coefficient differences between land and water, except at very low angles, cannot entirely account for the observed differences. Data on approximately 2700 Eg patches were studied for d r i f t information. About 10% of these were found to move through considerable distances, as far as at least 2000 km. The mean patch speed was 300 km/h, predomenantly westward. Data from Camden, Australia, shows after preliminary analysis westward draft as at Stanford. A preliminary investigation was also made of the p o s s i b i l i t y of using the oblique-incidence backscatter soundings to deduce electron density p r o f i l e s . F i r s t results were encouraging, albeit limited. 4. Bibliography. R. D. Egan, A.M. Peterson: "Auroral Noise at HF," J.G.R., vol.65, ppp.3830-32, Nov. 1960. R. D. Egan: "N(h) Profiles Deduced from Oblique Incidence Backscatter," i n W.J.G. Beynon (ed.) "Some Ionospheric Results Obtained during the IGY," Elsevier, Amsterdam, 1960. R.D. Egan, A.M. Peterson: "Backscatter Observations of Sporadic-E," i n "Ionospheric Sporadic E," E. K. Smith, S. Matsushita (eds.), Pergamon Press, 1962. 763
INTERDISCIPLINARY RESEARCH P r o j e c t 22.11 - A n a l y s i s of Synoptic Cosmic Ray Data 1. O b j e c t i v e s . T h i s p r o j e c t a t the New York U n i v e r s i t y was undertaken to analyse cosmic-ray data, i n p a r t i c u l a r , the r e l a t i o n s h i p between cosmic-ray i n t e n s i t y v a r i a t i o n s observed a t the ground and the geomagnetic f i e l d . I t was hoped to be able to deduce some of the p r o p e r t i e s of the geomagnetic f i e l d by such an a n a l y s i s . Comparison of such a deduced f i e l d with that obtained by s p h e r i c a l harmonic a n a l y s i s was expected to be h e l p f u l m suggesting an explanation for the d i s c r e p a n c i e s of the cosmic-ray geographical v a r i a t i o n , a u r o r a l isochasms and c e r t a i n ionospheric e f f e c t s with that that would be pre d i c t e d using the conventional centered and e c c e n t r i c r e p r e s e n t a t i o n s of the geomagnetic f i e l d . 2. Personnel. Arthur B e i s e r was p r o j e c t d i r e c t o r , working under Dr. B e i s e r ' s s u p e r v i s i o n were Donald E. Gotten and James Hurley. 3. R e s u l t s . Gotten studied the geomagnetic i m p l i c a t i o n s of the cosmic-ray d i u r n a l v a r i a t i o n and i t s spectrum. He concludes, i n h i s d o c t o r a l d i s s e r t a t i o n : "The amplitude and the l o c a l time of maximum (peak time) of the cosmic-ray nucleon d i u r n a l v a r i a t i o n (CEIDV) depend on l a t i t u d e , longitude and month. R e l a t i v e maxima and minima on t h e i r i s o p l o t contour maps correspond to r e l a t i v e extremums i n the geomagnetic f i e l d at or near the earth's s u r f a c e , and i n the geomagnetic r i g i d i t y . The CRDV map contours i n d i c a t e that the geomagnetic dipole and quadrupole moments and the e c c e n t r i c i t y of the geomagnetic f i e l d are s i g n i f i c a n t m i n f l u e n c i n g the a n i s o t r o p i c part of the cosmis ray f l u x . "When the amplitudes nj^ of the CRDV of a l l northern and e q u a t o r i a l neutron monitors are averaged over groups of months w i t h i n the IGY, and some p a i r s of s t a t i o n s with s i m i l a r v a l u e s of c u t o f f r i g i d i t y P^ are averaged together to smooth the data, then two peaks of ni p e r s i s t at approximately Pj. = 1 and 4 BV/c. These are r e l a t e d to a s i n g l e peak of k(P) i n the d i f f e r e n t i a l spectrum (4/3) k(P) cos 0 for the cosmic ray anisotropy. Here k(P) i s a f r a c t i o n of the i s o t r o p i c cosmic-ray f l u x a t i n f i n i t y and 0 i s the assjrmptotic longitude with r e s p e c t to an a x i s of anisot r o p y . P i s magnetic r i g i d i t y , or momentum per u n i t charge. The k(P) peak l i e s between P = 3.8 and 5.7 BV/c, and k(P) = 0.0039 + 0.002 for P>6 BV/c. At P < 3.8 BV/c s p e c t r a l c u t o f f , k(P) = 0. "A meaningful semi-diurnal v a r i a t i o n i n cosmic r a d i a t i o n i s found to be stro n g l y dependent upon p o s i t i o n on the e a r t h . I t i n d i c a t e s that the cosmic-ray anisotropy IS more narrowly c o l l i m a t e d than a cos 0 dependence, A s i g n i f i c a n t part of the observed semi-diurnal v a r i a t i o n i s dependent on u n i v e r s a l time. "The CRDV i s p r i m a r i l y caused by an anisotropy i n the cosmic-ray f l u x introduced by some mechanism w i t h i n the s o l a r system. T h i s a n i s o t r o p i c f l u x a r r i v e s from an assymptotic d i r e c t i o n 75° to 100° e a s t of the sun, i n the e c l i p t i c plane. A small CRDV component dependent on l o c a l time i s introduced by the i n c r e a s e d geomagnetic f i e l d on the sunward s i d e of the e a r t h , so as to show an apparent excess f l u x from opposite the sun. I f t h i s component were subtracted, the d i r e c t i o n of anisotropy s t a t e d above would be decreased, "A component of the CRDV i s dependent on u n i v e r s a l time, with amplitude of about 0.17o. Another component of the CRDV of amplitude 0.1% appears to be dependent on s i d e r e a l time, and to be caused by a cosmic-ray a n i s o t r o p i c f l u x i n the galaxy which came from 14 hours r i g h t a s c e n s i o n during the IGY. " I t I S p o s s i b l e to a s c r i b e most, i f not a l l , of the s p a t i a l v a r i a t i o n s i n cosmic- ray d i u r n a l i n t e n s i t y v a r i a t i o n on the e a r t h ' s s u r f a c e to the spectrum of the cosmic- 764
INTERDISCIPLINARY RESEARCH ray anisotropy and to the dip o l e and higher multipole geomagnetic f i e l d components. T h i s suggests t h a t , i n s o f a r as the immediate v i c i n i t y of the ear t h i s concerned, the e x t e r n a l geomagnetic f i e l d i s f a i r l y s a t i s f a c t o r i l y represented i n i t s i n t e r a c t i o n w i t h cosmic r a y s by the m u l t i p o l e c o e f f i c i e n t s obtained by a n a l y z i n g the s u r f a c e f i e l d . " S e v e r a l mechanisms appear r e s p o n s i b l e for the cosmic-ray anisotropy. F u r t h e r CRDV i n v e s t i g a t i o n s should attempt to separate v a r i o u s sources and f i n d t h e i r i n d i v i d u a l s p e c t r a and rig i d i t y - d e p e n d e n t a x i a l d i r e c t i o n s , r a t h e r than seek a s i n g l e source d i r e c t i o n . " Hurley st u d i e d the i n t e r a c t i o n of a streaming plasma with the magnetic f i e l d of a l i n e c urrent and c a l c u l a t e d the shape of the c a v i t y w a l l and the f i e l d i n s i d e the c a v i t y . T h i s i n i t i a l a n a l y s i s l e a d to the c o n c l u s i o n that the problem should be enlarged to inc l u d e the a n a l y s i s of the flow past a double wire(two dimensional magnetic d i p o l e ) , which would have a p p l i c a t i o n to plasma i n t e r a c t i o n s w i t h the geomagnetic f i e l d . 4. B i b l i o g r a p h y . James Hurley: " I n t e r a c t i o n of a Streaming Plasma with the Magnetic F i e l d of a Line C u r r e n t , " Phy. of F l u i d s , V o l . 4, No. 1, pp 109-111, Jan. 1961 Donald E . Gotten: "Geomagnetic I m p l i c a t i ns of the Cosmic Ray Di u r n a l V a r i a t i o n , and i t s Spectrum," Doctoral T h e s i s , New York U n i v e r s i t y , March 1, 1963 (Also F i n a l Report NASA NsG 108-61; ARPA 163-61; USASRDL DA- 36-039-SC-87171) 765
INTERDISCIPLINARY RESEARCH Project 22.12 - Analysis of Line Island Geomagnetic Data 1. Objectives, The geomagnetic data from Jarvis, Palmyra and Fanning Islands were acquired for the purpose of studying the equatorial electrojet i n the central Pacific, and i t was the principal objective of this project to make such a study. Two lines of approach were proposed, (a) a conventional study of the daily variation and of short-period events, such as bays and solar flar e effects, and (b) power-spectral analysis of short lengths of randomly disturbed record, using modern computer techniques. The periods to be emphasized were 3 mm to 4 hr. The two approaches d i f f e r i n that the former provides a general, qualitative picture of the electrojet, the l a t t e r expresses the quantitative relationship between the f i e l d changes at a pair of stations during a particular interval of time. I t provides their coherence, their phase difference and the r a t i o of their amplitudes, as a function of frequency, and enables more sophisticated conclusions to be reached. 2. Personnel. Dr. Ronald G. Mason was Project Director and Dr. K, Kunaratnam, now of the University of Ceylon, assisted with the computer programming. 3. Results. The most important conclusion reached from the study of daily variation was that the electrojet was centered on an average about 1/2°S of Jarvis, the most southerly of the three islands, or about 3/4°N of the magnetic equator. Thus a l l three stations were on i t s north side, and since Pal3miyra was so far away as to be only marginally influenced by i t , the d i s t r i b u t i o n of stations proved inadequate for an independent evaluation of the electrojet. No conclusion was possible, therefore, about the width of the electrojet, or the current d i s t r i b u t i o n within i t , except that i t can not d i f f e r much from the electrojet elsewhere. The observations are consistent with an anomalous band of eastward-flowing current at a height of about 100 km and about 600 km wide, centered near the magnetic equator and reaching a maximum around mid-day. A further conclusion reached from the daily variation studies was that both the mean latitude and the mean width of the electrojet change appreciably from day to day and from season to season. I t appears to move through about 1/2° of latitude during the year, i n a direction away from the svmnner hemisphere, and to increase i n width during the equinoxes. These various conclusions were supported by the short-period and spectral studies which, m addition to confirming the electrojet as a daytime phenomenon, pointed also to an apparent decrease i n the effective width of the electrojet with increase of frequency. However, the l a t t e r might well arise from inductive processes in the ocean. During the course of the spectral and short-period studies, i t became increas- ingly clear that the v e r t i c a l component of short-period fluctuations recorded on islands might be substantially modified by electric currents induced m the ocean. This has since been the subject of independent investigations on Christmas Island and Oahu, and i t now seems almost certain that the Jarvis and Fanning records were (influenced i n this way. This prevents any conclusion being reached about localized currents within the elect r o j e t . Since the effect of the ocean would be most marked for periods of a few hours, or less, i t is not l i k e l y that the longer periods i n - volved i n the study of daily variation would be affected to such an extent as to invalidate the general conclusions reached about the electrojet. 766
INTERDISCIPLINARY RESEARCH One f u r t h e r matter of i n t e r e s t to emerge from the s p e c t r a l s t u d i e s was that i n a l l cases power showed an I n v e r s e square dependence on frequency, w i t h m the range 3 min - 4 h r . T h i s r e s u l t i s c h a r a c t e r i s t i c of i n t e g r a t e d white noise and might a r i s e , for example, from applying a white-noise emf to a predominantly i n d u c t i v e c i r c u i t , as the lonosphere/conducting-earth system probably i s . However, i t i s not claimed t h a t t h i s r e s u l t i s p e c u l i a r to the e l e c t r o j e t ; i t i s q u i t e l i k e l y a property of magnetic no i s e i n g e n e r a l . 4. B i b l i o g r a p h y . a. Papers Presented at Meetings. R. G. Mason " S p a t i a l Dependance of Time V a r i a t i o n s on the Geomagnetic F i e l d on Oahu, Hawaii," F o r t y - F o u r t h Annual Meeting, AGU, A p r i l 1963, Washington, D, C. b. P u b l i s h e d Papers. R. G. Mason: "The E q u a t o r i a l E l e c t r o j e t i n the C e n t r a l P a c i f i c , " S c r i p p s I n s t i t u t i o n of Oceanography P u b l i c a t i o n 63-13, 1963. R. G. Mason: Paper d e a l i n g w i t h s p e c t r a l a n a l y s i s of data i s i n p r e p a r a t i o n . 767
INTERDISCIPLINARY RESEARCH P r o j e c t 22.13 - Study of E q u a t o r i a l Enhancement of T r a n s i e n t s and A c t i v i t y P a t t e r n s and Magnetic Storm Onsets a t Polar L a t i t u d e s 1. O b j e c t i v e s . T h i s p r o j e c t a t the U. S. Coast and Geodetic Survey, Geomagnetism D i v i s i o n , was organized to permit a n a l y s i s of the IGY magnetic data. a. Data from o b s e r v a t o r i e s near the magnetic dip equator were studied to determine how the " e l e c t r o j e t " responds to s o l a r f l a r e s and sudden commencements, the r e l a t i o n of t r a n s i e n t enhancement to d a y l i g h t or nighttime zones and seasons, and how the e l e c t r o j e t modifies the c h a r a c t e r of the s o l a r d a i l y v a r i a t i o n (S ) m e q u a t o r i a l r e g i o n s . Records from Guam and Koror, the L i n e I s l a n d s , and otSer o b s e r v a t o r i e s near the dip equator were examined u s i n g a s p e c i a l smoothing technique which i s capable of d i s p l a y i n g short-term changes i n S^. b. Records from h i g h - l a t i t u d e o b s e r v a t o r i e s were being s t u d i e d to determine the nature of onset phenomena and to t r y to r e l a t e d e s c r i p t i o n to theory, and c o r r e l a t i o n i n time of magnetic a c t i v i t y i n the northern and southern a u r o r a l zones. Refinements were sought m a technique for t r a n s l a t i n g measurements i n t o f i e l d - v e c t o r changes which can be p l o t t e d on maps, u t i l i z i n g r a p i d - r u n magnetograms, 2. Personnel. David G. Knapp, J . H. Nelson, John Gettemy, Louis Hurwitz and c o n s u l t a n t s p a r t i c i p a t e d i n t h i s study. 3. R e s u l t s . I n studying the S p a t t e r n a t Koror i t was found that the v e r t i c a l i n t e n s i t y curve there d i f f e r s from the expected p a t t e r n i n a way that suggests a north-south flow of c u r r e n t superimposed on the ordinary S p a t t e r n . T h i s e f f e c t was subjected to a t e s t by examining S i n d e c l i n a t i o n f o r other ( n o n e q u a t o n a l ) o b s e r v a t o r i e s d i s t r i b u t e d over the worSd. The t e s t seems to lend support to the hypothesis i n major a r e a s , but equivocal r e s u l t s are obtained i n one r e g i o n . 4. B i b l i o g r a p h y . David G. Knapp: some f e a t u r e s of magnetic storms i n high l a t i t u d e s , JGR Res., v. 66, pp. 2053-2085, 1961. David G, Knapp and John W. Gettemy: a new longitude e f f e c t i n the geomagnetic s o l a r - d a i l y v a r i a t i o n , JGR, v. 68, pp. 2411-2420, 1963. 768
INTERDISCIPLINARY RESEARCH P r o j e c t 22.14 - A n a l y s i s of B a l l o o n Data 1. O b j e c t i v e s . T h i s p r o j e c t a t the School of P h y s i c s , U n i v e r s i t y of Minnesota, provided some a s s i s t a n c e for the a n a l y s i s , p r e p a r a t i o n of manuscript, and p u b l i c a t i o n of r e s u l t s of the Minnesota cosmic-ray b a l l o o n p r o j e c t . 2. Personnel. The p r i n c i p a l i n v e s t i g a t o r s were E. P. Ney and J . R. Winckler; other s c i e n t i s t s a s s o c i a t e d with t h i s work were P. D. Bhavsar, J . A. E a r l , and L. E . Peterson. 3. R e s u l t s . T h i s p r o j e c t was i n t i m a t e l y connected with the o p e r a t i o n a l p r o j e c t (2.13) which I S reported m some d e t a i l ; the d i s c u s s i o n under that p r o j e c t i s a r e p r e s e n t a t i v e sampling of the r e s u l t s of the experiments and s t u d i e s r e f l e c t e d i n the bibliography below. 4. B i b l i o g r a p h y . J . R. Winckler, P. D. Bhavsar: "Low Energy S o l a r Cosmic Rays and the Geomagnetic Storm of May 12, 1959," JGR 65, pp. 2637-2655, 1960. E. P. Ney: "Cosmic Rays as r e c e i v e d a t the E a r t h , " Ap. J . Suppl. 44 to V o l . IV, pp. 371-377, June 1960. P. D. Bhavsar: " S c i n t i l l a t i o n Counter Observations of the Auroral X-rays During the Geomagnetic Storm of May 12, 1959," JGR 66, 679-692, March 1961. J . R. Winckler, E . P. Ney: " R a d i a t i o n from S o l a r F l a r e s , " L e t t e r s S c i e n c e , pp. 1276-1277, A p r i l 21, 1961, v o l . 133. J . R. Winckler: "Primary Cosmic Rays." R a d i a t i o n Research, 14, pp. 521-539, 1961. J . R. Winckler, P. D. Bhavsar and L. E. Peterson: "The Time V a r i a t i o n s of Solar Cosmic Rays during J u l y , 1959 at Minneapolis," JGR 66, pp. 995-1022, 1961. J . A. E a r l : "Balloon Measurement of So l a r Cosmic Rays a t F t . C h u r c h i l l , Canada, during J u l y 1959," JGR 66, No. 10, October 1961. J . R. Winckler: " S o l a r I n f l u e n c e s on the R a d i a t i o n F i e l d i n Space," Aerospace Medicine. V o l . 32, No. 10, pp. 893-901, October 1961. P. J . Kellogg and J . R. Winckler: "Cosmic Ray Evidence for a Ring C u r r e n t , " JGR., 66, 12, pp. 3991-4001, December 1961. J . R. Winckler: "Atmospheric Phenomena, E n e r g e t i c E l e c t r o n s and the Geomagnetic F i e l d , " Radio Propagation. V o l . 66D, N. 2, Mar-Apr. 1962, pp. 127-143. P. D. Bhavsar: "Gamma Rays from the Solar Cosmic Ray Produced Nuclear Reactions i n the E a r t h ' s Atmosphere and Lower L i m i t on the Energy of S o l a r Protons Observed at Minneapolis," JGR, 67, 7, pp. 2627-2638, J u l y 1962. J . R. Winckler, P. D. Bhavsar and K. A. Anderson: "A Study of the Pre- c i p i t a t i o n of E n e r g e t i c E l e c t r o n s from the Geomagnetic F i e l d , " JGR, 10, v o l . 67, pp. 3717-3736, September 1962. 769
INTERDISCIPLINARY RESEARCH J . R. Winckler: "Geomagnetic and I n t e r p l a n e t a r y E f f e c t s on S o l a r Cosmic Rays," J . Geophys. Res., Jou r n a l of the P h y s i c a l S o c i e t y of Japan, P a r t I I , pp. 353-360, 1962. P. D. Bhavsar, I n t . Conference on CR and E a r t h Storm: "S o l a r Cosmic Rays Event of September 3, 1960," Jou r n a l of the P h y s i c a l S o c i e t y of Japan. V o l . 17, Supplement A-11, 1962, P a r t I I , pp. 329-334. J . R. Winckler: "Balloon X-rays and the R a d i a t i o n B e l t s , " J o u r n a l of the P h y s i c a l S o c i e t y of Japan. Park I I , pp. 104-114, V o l . 17, Supplement A-11, 1962. J . R. Winckler: " S o l a r Cosmic Rays," The 1962 McGraw-Hill Yearbook of Science and Technology, p. 465, 1962. P. D. Bhavsar: "Auroral X-ray Observations a t Minneapolis, Minnesota, Jour n a l of the P h y s i c a l S o c i e t y of Japan. Part I , pp. 242-247, 1962. J . R. Winckler: "The Production and Propagation of E n e r g e t i c P a r t i c l e s From the Sun," Space S c i e n c e . 1963. 770
INTERDISCIPLINARY RESEARCH P r o j e c t 22.15 - A n a l y s i s of Synoptic Cosmic-Ray Data 1. O b j e c t i v e s . T h i s p r o j e c t a t the B a r t o l Research Foundation provided for a n a l y s i s of the v a r i o u s data c o l l e c t e d during IGY by B a r t o l s c i e n t i s t s , as w e l l as other r e l a t e d cosmic-ray d a t a . D e t a i l e d a n a l y s e s was conducted, w i t h p a r t i c u l a r emphasis upon the i n t e r p r e t a t i o n of the r e s u l t s i n terms of t h e i r r o l e i n understanding geophysical phenomena. The s i g n i f i c a n c e of c o r r e l a t i o n s with observations i n a l l of the other r e l e v a n t IGY d i s c i p l i n e s was i n v e s t i g a t e d t h e o r e t i c a l l y . An a n a l y s i s was made of the nature of the e a r t h ' s magnetic f i e l d as determined by a l l a v a i l a b l e shipboard cosmic-ray data. A r a t h e r complete map of isocosms was a v a i l a b l e for t h i s purpose. A c r i t i c a l examination of the methods heretofore u t i l i z e d for determining cosmic-ray coordinates from i n t e n s i t y v e r s u s l a t i t u d e data was made. At t e n t i o n was given to methods whereby the primary cosmic-ray i n t e n s i t y can be modified, for example, by the i n f l u e n c e of e l e c t r i c f i e l d s generated by e l e c t r o - magnetic i n d u c t i o n as a r e s u l t of the v a r i a t i o n of s o l a r magnetic f i e l d s a s s o c i a t e d with disturbances on the sun. The general p r i n c i p l e s involved i n these processes of electromagnetic i n d u c t i o n have an a p p l i c a t i o n outside of the realm concerned with the c r e a t i o n of cosmic ray e n e r g i e s , s i n c e s o l a r magnetic disturbances can c r e a t e e l e c t r i c f i e l d s i n the space surrounding the sun. Under s u i t a b l e c o n d i t i o n s , such e l e c t r i c f i e l d s can play an important r o l e i n modifying the energy of primary cosmic-ray p a r t i c l e s i n a manner as to produce phenomena i n t i m a t e l y r e l a t e d to those met with i n the case of magnetic storms. I n the implementation of t h i s i d e a , many mathematical problems became in v o l v e d . These were pursued through use of computing machine techniques. The data obtained i n the v a r i o u s p r o j e c t s at the B a r t o l Research Foundation were entered on IBM punched cards i n a manner such as to f a c i l i t a t e the mathematical a n a l y s e s and c o r r e l a t i o n s t u d i e s . 2. Personnel. M. A. Pomerantz was the p r o j e c t d i r e c t o r ; W. F . G. Swann, K. Nagashima, S. P. Duggal and V. R. Po t n i s were a l s o a s s o c i a t e d w i t h t h i s study. 3. R e s u l t s . By formulating an expr e s s i o n for the anisotropy of the primary cosmic ray i n t e n s i t y , the expected s o l a r d i u r n a l v a r i a t i o n of the i n t e n s i t y of the n u c l e o n i c component of the cosmic r a d i a t i o n a t sea l e v e l i s c a l c u l a t e d a t v a r i o u s geomagnetic l a t i t u d e s and longitudes for the fol l o w i n g c a s e s : a. the anisotropy i s produced outside the t e r r e s t r i a l magnetic f i e l d ( e x t r a - t e r r e s t r i a l o r i g i n ) , and b. the ani s o t r o p y i s produced i n s i d e the t e r r e s t r i a l magnetic f i e l d ( t e r r e s t r i a l o r i g i n ) . Values of the parameters which define the r i g i d i t y dependence of the anisotropy were determined from harmonic a n a l y s i s of the neutron monitor data recorded a t 47 s t a t i o n s during IGY. The r e s u l t s d i f f e r e d a p p r e c i a b l y from e a r l i e r c o n c l u s i o n s based upon considerably l e s s r i g o r o u s a n a l y s i s of the best a v a i l a b l e pre-IGY data. The amplitude of the d i u r n a l v a r i a t i o n appears to i n c r e a s e slowly from the equator to middle l a t i t u d e s , followed by a r a p i d decrease toward the poles. An i n c r e a s e i n the time of d i u r n a l maximum from equator to pole was a l s o r e v e a l e d . The s i g n i f i c a n t longitude e f f e c t p r e d i c t e d by theory was confirmed by comparisons between p a i r s of s t a t i o n s . A l a r g e r amplitude was observed a t mountain s t a t i o n s , i n accord with the t h e o r e t i c a l p r e d i c t i o n s . Processes i n which charged p a r t i c l e s can be a c c e l e r a t e d to cosmis-ray energies through electromagnetic i n d u c t i o n r e s u l t i n g from magnetic f i e l d s such as are en- countered^in sunspots were shown to be capable of producing protons with energies of 3 X 10 eV. The con d i t i o n s for c i r c u l a r o r b i t s , outward s p i r a l i n g , and inward s p i r a l i n g , were i n v e s t i g a t e d and defined. Other mechanisms, for example processes 771
INTERDISCIPLINARY RESEARCH by which a small amount of matter can s t e a l , from a l a r g e r amount of matter, energy which I t s t o r e s up for the subsequent purpose of converting i t i n t o cosmic-ray energy for i t s nucleons, were a l s o i n v e s t i g a t e d and t h e o r e t i c a l models developed. Comparisons of experimental r e s u l t s w i t h the p r e d i c t i o n s of i n c r e a s i n g l y s o p h i s t i c a t e d c a l c u l a t i o n s of geomagnetic th r e s h o l d r i g i d i t i e s were conducted. The most recent a n a l y s i s which takes i n t o account, i n a d d i t i o n to the c o n t r i b u t i o n s of higher order harmonics, the a p p r e c i a b l e penumbral e f f e c t s appears to provide an ac c u r a t e r e p r e s e n t a t i o n for most of the e a r t h , although small d i s c r e p a n c i e s s t i l l remain because of d i f f i c u l t i e s i n e v a l u a t i n g the penumbra. 4. Bib l i o g r a p h y . a. Papers Presented At Meetings M. A, Pomerantz, S. P. Duggal, and K. Nagashima: "The Unusual Cosmic Ray I n t e n s i t y I n c r e a s e s on November 12, 1960." COSPAR Space Symposium, F l o r e n c e , I t a l y , A p r i l 10-14 (1961). M. A. Pomerantz, S. P. Duggal, and K. Nagashima: " S o l a r D i u r n a l V a r i a t i o n of Cosmic Ray I n t e n s i t y . " I n t e r n a t i o n a l Conference on Cosmic Rays and the E a r t h Storm, Kyoto, Japan, September 4 - 1 4 (1961). W. F. G. Swann: "A General Approach to the Electromagnetic O r i g i n of Cosmic Ray Energy." I n t e r n a t i o n a l Conference on Cosmic Rays and the E a r t h Storm, Kyoto, Japan, September 4 - 14, (1961). W. F. G. Swann: "A General Approach to the Electromagnetic O r i g i n of Cosmic Ray Energy." New York meeting of the American P h y s i c a l S o c i e t y , January (1962). b. Published Papers W, F. G. Swann: "Processes Involved i n Electromagnetic A c c e l e r a t i o n of P a r t i c l e s to Cosmic-Ray E n e r g i e s . " J . F r a n k l i n I n s t . , v o l . 270, no. 5, 1960, pp. 343-52. K. Nagashima, V. R. P o t n i s , and M. A. Pomerantz: " T h e o r e t i c a l C a l c u l a t i o n of the S o l a r D i u r n a l V a r i a t i o n of the Cosmic Ray I n t e n s i t y . " I I Nuovo Cimento, no. 19, no. X, 1960, pp. 292-330. S. P. Duggal, K. Nagashima, and M. A. Pomerantz: " R i g i d i t y Dependence of S o l a r D i u r n a l V a r i a t i o n of Cosmic-Ray I n t e n s i t y . " J . Geophys. Res,, v o l . 66, no. 6, 1961, pp. 1970-73. W. F . G. Swann: "General Approach to the Electromagnetic O r i g i n of Cosmic- Ray Energy." Phys. Rev., v o l . 126, no. 2, 1962, pp. 757-62. M, A. Pomerantz, S. P. Duggal, and K. Nagashima: " S o l a r D i u r n a l V a r i a t i o n of Cosmic Ray I n t e n s i t y . " J . of the Phys. Soc. of Japan, v o l , 17, Supplement A-11, I n t e r n a t i o n a l Conference on Cosmic Rays and the E a r t h Storm, P a r t I I , 1962, pp. 464-68. A. E. Sandstrom, M. A. Pomerantz, B. 0. Gronkvist: "Sea L e v e l Cosmic Ray I n t e n s i t y and Threshold R i g i d i t y . " T e l l u s XV, no. 2, 1963, pp. 184-93. 772
INTERDISCIPLINARY RESEARCH P r o j e c t 22.16 - Research m Solar and S o l a r - T e r r e s t r i a l Problems 1. O b i e c t i v e s . T h i s p r o j e c t , c a r r i e d out a t the High A l t i t u d e Observatory, provided for r e s e a r c h on the c l o s e l y r e l a t e d problems of the o r i g i n and nature of s o l a r f l a r e s , the nature of the electromagnetic and corpuscular r a d i a t i o n s emitted by them, and ensuing t e r r e s t r i a l events. 2. Personnel. T h i s work was c a r r i e d out by W. R. S t e i g e r , on leave from the U n i v e r s i t y of Hawaii. 3. R e s u l t s . I n t e r e s t was p r i m a r i l y centered on the response of the upper atmosphere to electromagnetic and corpuscular r a d i a t i o n s . I n p a r t i c u l a r , some time was devoted to the a n a l y s i s of the e f f e c t s of the high a l t i t u d e n uclear explosion "TEAK" based on a s e r i e s of very unusual photographs. Major e f f o r t was devoted to the a n a l y s i s of the records of the I n d i r e c t F l a r e Detector l o c a t e d i n Hawaii. T h i s a n a l y s i s has y i e l d e d the background g a l a c t i c r a d i o noise as r e c e i v e d by the antenna i n Hawaii and the nature of the ionospheric absorption of t h i s g a l a c t i c noise and i t s r e l a t i o n s h i p to s o l a r z e n i t h angle and season. 4. B i b l i o g r a p h y . W. R. S t e i g e r and S. Matsushita, "Photographs of the High A l t i t u d e Nuclear E x p l o s i o n 'TEAK'", JGR, V o l . 65, 545-550, February 1960. James W. Warwick, "Observations of Cosmic Radio Noise at 18Mc/s i n Hawaii", JGR, V o l . 66, 57-66, January 1961. 773
INTERDISCIPLINARY RESEARCH P r o j e c t 22.17 - Charged P a r t i c l e O r b i t s i n the Geomagnetic F i e l d 1. O b j e c t i v e s . T h i s work a t the School of P h y s i c s , U n i v e r s i t y of Minnesota, provided f or a study of the c u t o f f r i g i d i t i e s using a b e t t e r approximation of the geomagnetic f i e l d than was used for some e a r l i e r c a l c u l a t i o n s . I n a d d i t i o n , other o r b i t problems i n the geomagnetic f i e l d were i n v e s t i g a t e d , i . e . , f e a t u r e s of the Van A l l e n geomagnetically trapped r a d i a t i o n , e t c . 2. Personnel. T h i s work was c a r r i e d out by P. J . Kellogg, 3. R e s u l t s . Using a machine program, the geomagnetic f i e l d was c a l c u l a t e d u s i n g a l l the moments through 2" as given by F i n c h and Leaton for epoch 1955. From t h i s d e s c r i p t i o n of the f i e l d , the p o s i t i o n of the cosmic ray equator was computed from o r b i t s of p a r t i c l e s a r r i v i n g a t the ear t h at a given p l a c e but with v a r i o u s r i g i d i - t i e s . Comparison w i t h observed v a l u e s of the geomagnetic f i e l d showed that the F i n c h and Leaton f i e l d approximation i s a c c u r a t e to about 3%, whereas e a r l i e r octupole c a l c u l a t i o n s were o f f some 157.; i t i s estimated t h a t c a l c u l a t e d r i g i d i t i e s a r e a c c u r a t e to w i t h i n 0.3 bev, assuming no c o n t r i b u t i o n s from other than the v e r t i c a l , whereas i t might a c t u a l l y be expected that the maximum i s 10° west of z e n i t h . Comparison of the c a l c u l a t e d r i g i d i t y with measured cosmic ray i n t e n s i t y showed an e r r o r of 0.4 bev, which could be due e i t h e r to a f a i l u r e of the 2^ pole expansion to re p r e s e n t adequately the s u r f a c e geomagnetic f i e l d , or to the presence of e x t e r n a l geomagnetic sources, i . e . , e l e c t r i c c u r r e n t s . C a l c u l a t i o n s of the c u t - o f f r i g i d i t i e s i n d i r e c t i o n s other than the z e n i t h were made f o r Guam f o r the b e n e f i t of experimenters who p a r t i c i p a t e d i n the cosmic ray e q u a t o r i a l e x p e d i t i o n . I n a d d i t i o n to geomagnetic evidence for the e x i s t e n c e of a r i n g c u r r e n t , a t l e a s t during magnetic storms there i s cosmic ray evidence, for low energy protons are observed a t Minneapolis only during the main phase of a magnetic storm, and the p a r t i c l e energies a re w e l l below the normal Stormer c u t - o f f energy a t that time. A model r i n g c u r r e n t , approximating i n i t s e f f e c t the d i f f u s e r i n g c u r r e n t a t t r i b u t - a b le to trapped charged p a r t i c l e s , was chosen to s i m p l i f y c a l c u l a t i o n s . I t was shown that the cosmic ray data permit e v a l u a t i o n of both the moment, M, of the cu r r e n t and i t s r a d i u s , R, whereas s u r f a c e geomagnetic measurements permit evalua- t i o n only of the quantity M/R^. Since cosmic ray data shows that c u t - o f f s r e t u r n to normal during the mam phase, i t must be assumed that the r i n g c u r r e n t s h r i n k s inward to maintain the s u r f a c e f i e l d n e g ative. The discrepancy between measured and c a l c u l a t e d c u t - o f f r i g i d i t i e s a t quiet times, i . e . , at northern l a t i t u d e s the measured value i s s u b s t a n t i a l l y l e s s than the c a l c u l a t e d v a l u e , i s taken as evidence for a permanent, quiet-time r i n g c u r r e n t , which i s i n t e n s i f i e d during storms. 4. B i b l i o g r a p h y . P. J . Kellogg: " C a l c u l a t i o n s of Cosmic Ray T r a j e c t o r i e s near the Equator," JGR, v o l . 65, pp. 2701-2704, Sept. 1960. P. J . Kellogg, J . R. Winckler: "Cosmic Ray Evidence for a Ring C u r r e n t , " JGR, v o l . 66, pp. 3991-4001, Dec. 1961. 774
INTERDISCIPLINARY RESEARCH P r o j e c t 23.1 - S p e c i a l Research Surveys by D i s t i n g u i s h e d S c i e n t i s t s from Abroad 1. O b j e c t i v e s . T h i s p r o j e c t , administered under the s u p e r v i s i o n of Dr. M. A. Tuve, by the Department of T e r r e s t r i a l Magnetism, Carnegie I n s t i t u t i o n of Washington, provided for v i s i t s to r e s e a r c h o r g a n i z a t i o n s i n the United S t a t e s of d i s t i n g u i s h e d s c i e n t i s t s from abroad, who had p a r t i c i p a t e d i n the IGY programs of t h e i r own c o u n t r i e s . These v i s i t o r s j o i n e d t h e i r colleagues i n the U. S. to d i s c u s s IGY r e s u l t s , p a r t i c u l a r l y from an i n t e r d i s c i p l i n a r y point of view, to j o i n i n c o l l a b o r a - t i v e a n a l y s i s , and to s t i m u l a t e f r e s h a n a l y t i c a l a t t a c k s on the body of IGY data. 2. R e s u l t s . T h i s program had no d i r e c t s c i e n t i f i c r e s u l t s , a t l e a s t as c h a r a c t e r i z e d by d e t a i l e d r e p o r t s , although m many i n s t a n c e s r e s e a r c h papers r e s u l t e d from the c o l l a b o r a t i v e a n a l y t i c a l e f f o r t s . A l i s t of the v i s i t o r s and the r e s e a r c h i n s t i t u t i o n s v i s i t e d , f o l l o w s : J . B a r t e l s , U n i v e r s i t y of Gottingen, Germany Dept. of T e r r e s t r i a l Magnetism High A l t i t u d e Observatory RAND U n i v e r s i t y of Minnesota D. R. Bates, Queen's U n i v e r s i t y , B e l f a s t , N. I r e l a n d C e n t r a l Radio Propagation L a b o r a t o r i e s Harvard College Observatory Yerkes Observatory B. B o l i n , U n i v e r s i t y of Stockholm, Sweden S c r i p p s I n s t i t u t i o n of Oceanography Weather Bureau Woods Hole Oceanographic I n s t i t u t i o n K. E. B u l l e n , U n i v e r s i t y of Sydney, A u s t r a l i a Dept. of T e r r e s t r i a l Magnetism Carnegie-Andes Seismic Networks, Peru, B o l i v i a , C h i l e , Argentina R. A. Cox, National I n s t i t u t e of Oceanography, England F i s h e r i e s Research Board, Naraimo, B r i t i s h Columbia John Hopkins Chesapeake Bay I n s t i t u t e S c r i p p s I n s t i t u t i o n of Oceanography U n i v e r s i t y of Washington Woods Hole Oceanographic I n s t i t u t i o n G. E. R. Deacon, National I n s t i t u t e of Oceanography, England Harvard U n i v e r s i t y Honolulu P a c i f i c Science Congress I n s t i t u t e Eng. Res. at Berkeley, C a l i f . John Hopkins U n i v e r s i t y Lamont G e o l o g i c a l Observatory National Oceanography Data Center Stevens I n s t i t u t e S c r i p p s I n s t i t u t i o n of Oceanography U. S. Coast and Geodetic Survey U n i v e r s i t y of Washington Woods Hole Oceanographic I n s t i t u t i o n U n i v e r s i t y of B r i t i s h Columbia New York U n i v e r s i t y 775
INTERDISCIPLINARY RESEARCH G. D i e t r i c h , K i e l U n i v e r s i t y , K i e l , Germany Columbia U n i v e r s i t y Johns Hopkins U n i v e r s i t y Lamont G e o l o g i c a l Observatory New York U n i v e r s i t y S c r i p p s I n s t i t u t i o n of Oceanography State College of Oregon U. S. Weather Bureau U. S. Navy Hydrographic O f f i c e U n i v e r s i t y of Washington U n i v e r s i t y of Miami WDC-A at Texas A and M Woods Hole Oceanographic I n s t i t u t i o n M. A. E l l i s o n , Dublin I n s t i t u t e of Advanced S t u d i e s , I r e l a n d C e n t r a l Radio Propagation L a b o r a t o r i e s High A l t i t u d e Observatory Harvard U n i v e r s i t y McMath-Hulbert Observatory Sacramento Peak Observatory School of P h y s i c s , Minneapolis I . Escobar, U n i v e r s i t y of La Paz, B o l i v i a Naval Research L a b o r a t o r i e s U. S. Weather Bureau U n i v e r s i t y of Chicago A. L. Hales, U n i v e r s i t y of Witwatersgrand, So. A f r i c a C a l i f o r n i a I n s t i t u t e of Technology Dept. of T e r r e s t r i a l Magnetism U n i v e r s i t y of Kansas U n i v e r s i t y of Wisconsin M. Hasegawa, U n i v e r s i t y of Kyoto, Japan Dept. of T e r r e s t r i a l Magnetism Naval Research L a b o r a t o r i e s National Academy of Sciences National Science Foundation RAND High A l t i t u d e Observatory U. S. Coast and Geodetic Survey U n i v e r s i t y of Hawaii P. Herrinck, Meteorological I n s t . , L e o p o l d v i U e , Congo Dept. of T e r r e s t r i a l Magnetism C e n t r a l Radio Propagation L a b o r a t o r i e s A i r Force Cambridge Research L a b o r a t o r i e s F r e d e r i c k Magnetic Observatory Pennsylvania State U n i v e r s i t y S t a t e U n i v e r s i t y of Iowa Ohio S t a t e U n i v e r s i t y U. S. Coast and Geodetic Survey U n i v e r s i t y of Chicago K. Hidaka, Tokyo U n i v e r s i t y , Japan Honolulu P a c i f i c Science Congress, Hawaii P a c i f i c Science Board, D. C. O f f i c e of Naval Research U. S. Navy Hydrographic O f f i c e U, S, Weather Bureau WDC-A at Texas A and M Woods Hole Oceanographic I n s t i t u t i o n 776
INTERDISCIPLINARY RESEARCH A. P. M i t r a , National P h y s i c s , Lab., New D e l h i , I n d i a C e n t r a l Radio Propagation Laboratory I n s t i t u t e for Space Research (NASA) New York Naval Research Laboratory Pennsylvania State U n i v e r s i t y Rennselaer P o l y t e c h n i c I n s t i t u t e Stanford U n i v e r s i t y Stanford Research I n s t i t u t e U n i v e r s i t y of Alaska U n i v e r s i t y of Michigan Y a l e U n i v e r s i t y M. N i c o l e t , R a d i a t i o n S e r v i c e , B r u s s e l s , Belgium C o r n e l l U n i v e r s i t y Harvard College Observatory High A l t i t u d e Observatory Pennsylvania S t a t e U n i v e r s i t y W. R. Piggot, DSIR Radio Research S t a t i o n , Slough, England A i r Force Cambridge Research L a b o r a t o r i e s C e n t r a l Radio Propagation L a b o r a t o r i e s C o r n e l l U n i v e r s i t y Dartmouth College High A l t i t u d e Observatory Naval Research Laboratory Stanford U n i v e r s i t y U n i v e r s i t y of Al a s k a U n i v e r s i t y of Colorado W. Schwerdtfeger, U n i v e r s i t y of Buenos A i r e s , Argentina High A l t i t u d e Observatory U. S. Weather Bureau U n i v e r s i t y of C a l i f o r n i a a t Los Angeles U n i v e r s i t y of Chicago U n i v e r s i t y of Wisconsin S. Suyehiro, M e t e r o l o g i c a l Research I n s t i t u t e , Tokyo A i r Force O f f i c e S c i e n t i f i c Research C a l i f o r n i a I n s t i t u t e of Technology Dept. of T e r r e s t r i a l Magnetism Lamont G e o l o g i c a l Observatory U. S. Coast and Geodetic Survey I n a d d i t i o n to the extended v i s i t s made by the above group, s p e c i a l encourage- ment was given to a l a r g e r group of i n t e r n a t i o n a l c o l l a b o r a t o r s who were asked to provide summaries of the a c t i v i t i e s and r e s u l t s of the IGY i n t h e i r own s p e c i a l f i e l d s , as viewed f i v e y e a r s l a t e r . Small funds were made a v a i l a b l e for manuscript c o s t s and i n c i d e n t a l s , and these papers c o n s t i t u t e d a l a r g e part of the m a t e r i a l presented a t the IGY Symposium i n Los Angeles during August 1963. These papers were published m "Research m Geophysics" by the MIT P r e s s under the aus p i c e s of the National Academy of S c i e n c e s . 777
INTERDISCIPLINARY RESEARCH P r o j e c t 23.2 - V i s i t i n g S c i e n t i s t Program 1. O b j e c t i v e s . I n the proposal for the grant submitted by the U n i v e r s i t y of Chicago to sponsor the v i s i t s of outstanding p h y s i c a l s c i e n t i s t s , the f o l l o w i n g o b j e c t i v e s for the program were s t a t e d : a. To s t i m u l a t e r e s e a r c h through the v i s i t s of outstanding r e s e a r c h workers and to make a v a i l a b l e funds for t r a v e l of these i n v e s t i - gators to c e n t e r s of s c i e n t i f i c r e s e a r c h i n the United S t a t e s , these c e n t e r s to be the choice of the v i s i t i n g s c i e n t i s t . b. That the U n i v e r s i t y of Chicago and the E n r i c o Fermi I n s t i t u t e s h a l l be the host i n s t i t u t i o n and that o f f i c e space w i l l be provided for the v i s i t i n g s c i e n t i s t . c . That s p e c i a l emphasis i n the s e l e c t i o n of the v i s i t o r s h a l l be based upon t h e i r a b i l i t y to c r o s s f i e l d s of r e s e a r c h i n cosmic r a y s , high energy a s t r o p h y s i c s , s o l a r and plasma p h y s i c s i n t e r p l a n e t a r y magnetic f i e l d s and s o l a r - t e r r e s t r i a l r e l a t i o n s h i p s . d. The v i s i t i n g s c i e n t i s t i s not r e s t r i c t e d to the data of the IGY e f f o r t , although i n many cases he may wish to u t i l i z e the information obtain- able from IGY c e n t e r s and may wish to v i s i t these c e n t e r s . 2. Operations and R e s u l t s . Based on the above c r i t e r i a , s e v e r a l s c i e n t i s t s i n other c o u n t r i e s were approached i n f o r m a l l y about the program i n which they would v i s i t many c e n t e r s i n the United S t a t e s ( i n c l u d e d i n t h i s c o n s i d e r a t i o n were L o v e l l ( E n g l and); R. Lust (Germany); I . S. Schklovsky (U.S.S.R.); Ginsberg (U.S.S.R.), A. E. Chudakov (U.S.S.R.); B. P e t e r s (Denmark); H. E l l i o t ( E n g l a n d ) . I t q u i c k l y became apparent that i t was d i f f i c u l t to a t t r a c t f i r s t - r a t e s c i e n t i s t s j u s t on the b a s i s of t r a v e l and general exchange of information. I n s t e a d they p r e f e r r e d to center themselves a t an i n s t i t u t i o n where they could do some work r e l a t e d to t h e i r c u r rent i n t e r e s t and be i n a p o s i t i o n to c a r r y i n v e s t i g a t i o n s back to t h e i r own country. I n view of the above d i f f i c u l t i e s i n the e a r l y stages of s e t t i n g up t h i s program, i t was subsequently proposed to i n v i t e v i s i t i n g s c i e n t i s t s to p a r t i c i p a t e or conduct t h e i r r e s e a r c h work a t Chicago, and to v i s i t as they pleased other groups i n the country from time to time. The c r i t e r i a for the success of the program as r e v i s e d i s thus based on two p o i n t s : (1) What c o n t r i b u t i o n s has the v i s i t i n g s c i e n t i s t through h i s v i s i t been able to make i n the understanding or a n a l y s i s of IGY data as represented, for example, by p u b l i c a t i o n ? And ( 2 ) , to what extent has the v i s i t i n g i n v e s t i g a t o r been a b l e to c a r r y back t o h i s homeland new ideas and techniques to s t i m u l a t e s c i e n c e i n h i s own country? The main expenditures of funds i n t h i s program were as f o l l o w s : a. Dr. Ismael Escobar, D i r e c t o r C hacaltaya Observatory, B o l i v i a . Dr. Escobar v i s i t e d over the period December 1959 through June 1960, during which time he learned and i n v e s t i g a t e d the methods of measurements with neutron i n t e n s i t y monitors. I n c o l l a b o r a t i o n with the Chicago cosmic-ray group, he arranged w i t h h i s C h a c a l t a y a laboratory for a program of neutron i n t e n s i t y monitors a t high a l t i t u d e a t the equator. Through a g i f t from the U n i v e r s i t y of Chicago of the neutron i n t e n s i t y monitor formerly used on the U. S. a n t a r c t i c expeditions by the U n i v e r s i t y of Chicago, 1955 - 1957 (U.S.S. Atka and U.S.S. Arneb) he q u i c k l y e s t a b l i s h e d the monitor m B o l i v i a . With t h i s program the Chacaltaya observatory now continuously records neutron monitor i n t e n s i t y and r e p o r t s to the IGY-IQSY data c e n t e r s . Already r e s e a r c h based on these observations i s underway i n Peru. 778
INTERDISCIPLINARY RESEARCH b. Dr. I . Kondo, Department of P h y s i c s , Nagoya U n i v e r s i t y , Japan. Dr. Kondo was i n v i t e d for the period September 1962 to September 1964. Being a s c i e n t i s t of c o n s i d e r a b l e m a t u r i t y , but working i n a l a r g e group, h i s f i r s t v i s i t to the United S t a t e s gave him an opportunity to develop h i s independence i n s c i e n t i f i c i n v e s t i - g a t i o n . To understand the importance of h i s appointment, i t i s e s s e n t i a l to note that following the U n i v e r s i t y of Chicago a n t a r c t i c expeditions with neutron i n t e n s i t y monitors, r e s e a r c h showed that the geomagnetic f i e l d could both be analyzed i n more d e t a i l for i t s e f f e c t on the c u t - o f f of charged p a r t i c l e s , and the cosmic-ray primary spectrum could be s t u d i e d over a period of y e a r s . The Japanese Government l a t e r undertook an extension of t h i s type of observation on t h e i r s h i p , the Soya, the data from which Dr. Kondo and h i s c o l l e a g u e s were working. Therefore, i t i s a major c o n t r i b u t i o n of Dr. Kondo that the combined a n a l y s i s of Soya and Chicago data have l e d to the most d e f i n i t i v e d e s c r i p t i o n of changes i n the primary cosmic- ray spectrum y e t undertaken i n t h i s s o l a r c y c l e . Dr. Kondo a l s o extended through the use of the U n i v e r s i t y Computation Center the i n v e s t i g a t i o n of s u i t a b l e geomagnetic coordinates for the d e s c r i p t i o n of the cosmic-ray cut o f f s . The s i t u a t i o n i n t h i s f i e l d i s much c l e a r e r now. S e r i o u s con- s i d e r a t i o n I S being given to preparing a comprehensive monograph on geomagnetic c u t - o f f s for cosmic r a d i a t i o n and t h e i r i m p l i c a t i o n s for geomagnetic f i e l d a n a l y s i s . I n a d d i t i o n to the above work. Dr. Kondo has worked with the data from a Discoverer s a t e l l i t e experiment c a r r i e d out by C. Y. Fan and J . A. Simpson. T h i s work i s m progress and i s providing e x c e l l e n t experience for Dr. Kondo i n s a t e l l i t e data a n a l y s i s p r i o r to h i s r e t u r n to Japan. c. H. S. G h i e l m e t t i -- P h y s i c i s t , Argentina Atomic Energy Commission. Dr. G h i e l m e t t i i s a young man s t r o n g l y recommended by the Argentine Cosmic-Ray Group d i r e c t e d by Juan Roederer. The e x i s t e n c e of the grant funds made i t p o s s i b l e to b r i n g him to the U n i v e r s i t y of Chicago by providing a guarantee for t h i s t r a v e l and l i v i n g expenses. A f t e r he a r r i v e d , i t was determined that the proposed work would more properly be supported under an IGY data grant, and a c c o r d i n g l y , funds for h i s support were t r a n s f e r r e d . However, i t should be pointed out that the e x i s t e n c e of the grant enabled Mr. G h i e l m e t t i to be brought to Chicago, i n i t i a l l y , and while there he learned to handle neutron i n t e n s i t y monitor data and r e l a t e d s o l a r and geophysical parameters. T h i s l e d to p u b l i c a t i o n of h i s paper, "The Spectrum and Propagation of R e l a t i v i s t i c S o l a r F l a r e P a r t i c l e s during J u l y 17-18, 1959" which provided him a base f o r h i s t h e s i s requirements f o r the doctorate degree i n Argentina a f t e r h i s r e t u r n . F o l l o w i n g d i s c u s s i o n s w i t h Juan Roederer, G h i e l m e t t i decided to l e a r n b a l l o o n i n g techniques from the U n i v e r s i t y of Chicago group which gave him the know-how and s p e c i a l techniques concerned with small balloon launchings and apparatus for such purposes. T h i s l e d to the establishment of a b a l l o o n - f l i g h t program i n Argentina f o l l o w i n g h i s r e t u r n . These i n v e s t i g a t i o n s have centered i n the s t u d i e s of r a d i a t i o n s i n the upper atmosphere m the region of the South American magnetic anomaly -- these s t u d i e s c u r r e n t l y are underway under the d i r e c t i o n of G h i e l m e t t i and Roederer and have been q u i t e s u c c e s s f u l . 3. B i b l i o g r a p h y . H. S. G h i e l m e t t i : "The Spectrum and Propagation of R e l a t i v i s t i c S o l a r F l a r e P a r t i c l e s during J u l y 17-18, 1959," JGR. V o l . 66, No. 6, 1961. I . Kondo, M. Kodama, T. Makino: "Yearly Change i n L a t i t u d e E f f e c t of Cosmic-Ray Nucleonic Component a t Sea L e v e l , " T r a n s . . AGU Vol . 44, No. 1, 1963 ( a b s t r a c t ) 779
INTERDISCIPLINARY RESEARCH I . Kondo, M. Kodama: "Geographic D i s t r i b u t i o n of V e r t i c a l Cosmic-Ray Threshold R i g i d i t i e s , " Proc. I n t . Conf. Cosmic Rays. J a i p u r , I n d i a ( a b s t r a c t i n Trans. AGU. Vol 45, No. 1, 1964 I . Kondo Y. Sekido, T. Murayama, e t a l i a : "Studies on the Anisotropy of Cosmic RAYS with the Cosmic Ray Telescope i n Nagoya," Proc. I n t . Conf. Cosmic Rays. J a i p u r , I n d i a 780
