Global Tropospheric Chemistry A Plan for Action (1984) / Chapter Skim
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APPENDIXES
APPENDIXES
Pages 169-188
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From page 171... ...
In the United States, these programs, active in several agencies are formally coordinated through the Subcommittee on Atmospheric Research of the Committee on Atmospheres and Oceans, which is established under the Federal Coordinating Council for Sciences, Engineering, and Technology. None of the current programs includes all of the Global Tropospheric Chemistry Program elements recommended in this report, and all of them together wig not, without significant augmentation, achieve the goals of the recommended global program.
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From page 172... ...
to study the chemistry of the global troposphere and its interaction with the stratosphere. The first phase of the project, aimed at developing and validating measurement techniques for HxOy and NOx trace species in tropospheric chemical cycles, is designed to lead to the development and implementation of a cooperative global tropospheric chemistry research program with the goal of understanding the chemical cycles that control the composition of the global troposphere and its charlges.
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From page 173... ...
The time schedules contained in this federal plan call for preliminary assessment of the research results by 19851986 and a more complete assessment by 1988-1989. OTHER RELATED PROGRAMS In addition to the above programs that have regionalto global-scale tropospheric chemistry as their major thrust, several mission agencies support work that is applicable to the research goals of a global tropospheric chemistry program.
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From page 174... ...
A major fraction of this activity is directed toward understanding and characterizing problems within urban and regional air sheds with focus on criteria pollutants, hazardous pollutants, long-range transport, transformations, particles, vehicular emissions, and large-scale and long-term effects of air pollution on the biosphere. An analysis ofthis program is beyond the scope ofthis report, but the program has produced, and continues to produce, results of immediate application to global tropospheric chemistry investigations.
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From page 175... ...
These sensors have recently shown the ability to detect regions of elevated haze layers and aerosol loading in the troposphere. A second class of instruments includes passive remote sen sors that measure spectral emission or absorption of the Space Shuttle, and possibly spaceborne pallets or atmospheric molecules with external sources of radia free flyers of shorter duration missions.
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From page 176... ...
The important variable parameters for study in specifying the model are the bidirectional reflectivity ofthe ground, the aerosol optical thickness, the relative humidity and amount of water vapor, the composition of the aerosols, and their size distribution. The computed radiation characteristics will be com pared with experimental results.
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From page 177... ...
External sources of radiation for nadir-viewing experiments include upwelling thermal radiance of the earth-atmosphere system, reflected radiation from the surface ofthe earth, and scattered radiation from molecules and aerosols in the atmosphere. Compared to detection of direct solar radiation through the atmosphere, as in stratospheric solar occultation measurements, these sources of radiation are relatively weak and require more sensitive detection instruments.
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From page 178... ...
Although interesting absorption and emission lines of major atmospheric molecules lie in this region, inversion of the radiance measurement to molecular concentrations is complicated by the complexity ofthe radiative transfer equation, which makes it difficult to quantitatively invert radiances to obtain molecular concentrations. A summary of the current passive remote sensors developed under the NASA remote sensing program has been reviewed by Levine and Allario2 and will not be discussed further.
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From page 179... ...
For example, in probing the troposphere from the top of the atmosphere in the nadir mode, the laser beam has the potential to probe down to the surface of the atmosphere, and through the process of molecular absorption and range gating (to be discussed later) , the vertical distribution of molecular concentrations, aerosols, and meteorological parameters can, in principle, be obtained to a spatial resolution of c 0.1 km.
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From page 180... ...
The purpose of this workshop was to define the long-range role of passive remote sensors in tropospheric research and to identify the technology advances necessary to implement that prescribed role. Recommendations and conclusions from the two panels of the workshop attendees are given below.
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From page 181... ...
Active remote sensors under development, however, have high potential to meet some of the major scientific requirements for measurements in the troposphere from an airborne platform, including vertical resolution of approximately 1 km for major species, vertical range extending to the ground, day/night operation, true column-content measurements, and inherent high spectral resolution and tunability to measure tropospheric species simultaneously and uniquely in a background of interfering gases. For applications to space platforms, however, major technological developments must be made in the sources themselves, including high power and efficiency, improved collimation and spectral purity, wider tunability, and higher frequency and amplitude stability.
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From page 182... ...
Therefore, in generating scientific requirements for satellite missions, the science requirements must be tempered somewhat by the status of laser technology, and, in some cases, priorities for missions must be dictated by availability of laser technology.
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From page 183... ...
APPENDIX ~ Element Cycle Matrices A matrix approach was used in an effort to systematically, but simply, indicate what is currently known about the primary species involved in the sulfur, carbon, halogen, nitrogen, and trace element cycles, as well as the importance of the species in each cycle to an overall understanding of that cycle. Individual species were rated to indicate current knowledge and their importance in each cycle relative to their major sources, removal and transformation processes, and tropospheric distribution.
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From page 184... ...
B A A A A A Dry (ocean) A A A A A A Transformation Homogeneous aq.phase C B B B C B Homogeneous gas phase B A B B A Heterogeneous B A A A B A Distribution B B A A B C Interaction with other HrO' C C C C C cycles N N H
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From page 185... ...
2(1) Homogeneous gas phase 1 1 ( )
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From page 186... ...
phase B C C B C B Homogeneous gas phase A B B A B B Heterogeneous A A A A B B Distribution A A A A A B Interactions with HxO' HxO' HxO' HxO other cycles C C C aKnowledge: 1 = low, 4 = high; Importance: 1 = high, 4 = low. bUrgency factor: A = extremely urgent for that cycle, B = considerably urgent, C = moderately urgent, D = of little urgency.
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From page 187... ...
phase Homogeneous gas phase Heterogeneous Distribution Interactions with other cycles C B B B B B C C D D D B C C B C B B C C C C B C B B B - B A A - B C B B C Aerosol B C C A B B C C C D D D B C C B C C C C C C C C C C A B S N HxOy Aerosol A B B A B B B C C C C C B B C C B C B B C C C C B B B A B B C C C C C C B B B B B B C C C C C C B B B B A B - A B A A A A B A A A A HxOy Aerosol HxOy Aerosol aKnowledge: 1 = low, 4 = high; Importance: 1 = high, 4 = low. 6Urgency factor: A = extremely urgent for that cycle, B = considerably urgent, C = moderately urgent, D = of little urgency.
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From page 188... ...
A A C D Transformation Homogeneous aq.phase B C B Homogeneous gas phase B B B C Heterogeneous B C B Distribution A A C C Interactions with H `O' S H':Oy other cycles S Aerosol C Aerosol aKnowledge: 1 = low, 4 = high; Importance: 1 = high, 4 = low. bUrgency factor: A = extremely urgent for that cycle, B = considerably urgent, C = moderately urgent, D = of little urgency.
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