Biographical Memoirs Volume 68 (1995) / Chapter Skim
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Jacob Aall Bonnevie Bjerknes
Jacob Aall Bonnevie Bjerknes
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From page 3... ...
It was Jack's father, the famous physicist and geophysicist Vilhelm Bjerknes, who set the stage for the research leading up to this discovery, but Jack was the principal performer. FAMILY BACKGROUND The name Bjerknes comes from a family farm in southeastern Norway where some of Jack's ancestors livecI.
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With this theorem, Vilhelm Bjerknes realized that he now was in possession of the complete set of hyciroclynamic/thermoclynamic equations that govern the motion of nonhomogeneous fluids. Encouraged by his Swedish colleagues, among them the famous chemist Svante Arrhenius en c!
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In cooperation with his Carnegie assistants, the Swecle Johan Sancistrom, ant! the Norwegians Olaf Devik and Theoclor Hesselberg, he published a substantial work, Dynamic Meteorology and Hydrography.
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As the war went on, the situation for the Leipzig Geophysics Institute worsened, with lack of labor and food shortages. Through the intervention of the Norwegian oceanographers Fridtjof Nansen anct Bj0rn HelIand-Hansen, a professorship was established for Vilhelm Bjerknes in Bergen in western Norway.
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From page 7... ...
Furthermore, Jack stated in his paper that warm air ascends along the sloping frontal sur· faces, causing bancis of clouds and precipitation to form along the fronts, whereas the coicI air sinks en cl spreads out along the ground. He notecl that these vertical motions represent a reduction of the potential energy, which couIcI account for the formation of the cyclone's kinetic energy, in agreement with MarguTes's theory publishecl fifteen years earlier.
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~ . ~ , , ~ ~ / ~ ~ ado ~ ~ ~ Cold: TFo~~ ~ Cold ~> u~ ale eri\, line FICLRE 1 jack Weakness cyclone model ~reamUnes, clouds, and precipF tadon and verOca1 cros~secdons north and south of the center.
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is born as Solberg's initial wave on the polar front, develops into Jack Bjerknes's ideal cyclone, and finally suffers the Rer~eroni~n orcl,,sion death." It is noteworthy, however, that many of the features of the life cycle of cyclones were already contained in Jack's original paper, which he wrote in the fall of 1918. In 1920 Jack Bjerknes was appointed head of the Weather Forecasting Office for western Norway.
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front at the ground, and the vorticity connected with this trough was correctly ascribed to vertical stretching as the warm air descends cold front surface. clown the sloping This is the first attempt toward a dynamic treatment of the upper wave.
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Godske ant! Jack wrote an interesting paper together on instability of fronts; and Godske wrote the greater part of an extensive volume titled Dynamic Meteorology and Weather Forecasting, coauthored by Gociske, Bergeron, Jack Bjerknes, and R
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One cannot say they solved the problem, but they threw new light on it, and their work inspirer! their first cloctoral stuclent, Jule Charney, to come out with the first mathematical solution describing growing waves on a baroclinic current.
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Basecl on Jeffreys's theory, Jack Bjerknes started a major research project on the general circulation of the atmosphere. His principal co-worker was Yale Mintz; but invites!
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Jack first took up the study of the warming of the North Atian tic Ocean at the beginning of the century and found that it could be explained by an increased wind drag that speecled up the Gulf Stream. The interannual variations of the sea surface temperature in the North Atlantic were his next study subject.
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To account for variations in rainfall, Jack envisaged a vertical air circulation along the equator in the Pacific area, which he called the Walker circulation, since its strength would vary with Walker's southern oscillation. As a result of his investigations, we now have a coherent picture of these large-scare processes in the equatorial Pacific.
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G Wurtele (Selected Papers of Jacob Call Bonnevie Bjerknes, Western Periodicals Co., North Hollywood, Calif., 1975~.
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Olav, 1947 Vega Medal, Swedish Society of Geography, 1958 International Meteorological Organization Prize, World Meteorological Organization, 1959 Carl-Gustaf Rossby Award, American Meteorological Society, 1960 Robert M Losey Award, Institute of Aerospace Sciences, 1963 President, Meteorological Association, International Union of Geodesy and Geophysics, 1948-51 National Medal of Science, 1966 Honorary Member and Fellow, American Meteorological Society, 1966 Honorary Doctor of Laws, University of California, 1967 Member, Royal Norwegian Academy of Sciences, Royal Swedish 17 Academy of Sciences, Danish Academy of Technical Sciences, Academy of Sciences (India)
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Life cycle of cyclones and the polar front theory of atmospheric circulation. Geofys.
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A 7:41-46. 1955 The transfer of angular momentum in the atmosphere.
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In Proceedings of the Symposium on the Arctic Heat Budget and Atmospheric Circulation, Lake Arrowhead, Calif., Jan.
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: 2 1 2- 1 7 . 1974 Atmospheric Teleconnections from the Equatorial Pacific During 1963-67.
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