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The photochemistry of the paleoatmosphereRecent progress in the understanding of the chemistry and photochemistry of the paleoatmosphere is reviewed with emphasis on the application of photochemical models to the investigation of the evolution of the atmosphere. Photochemical calculations are presented which show that a primordial highly reducing atmosphere composed of methane and ammonia, if it formed at all, would be short-lived in the presence of solar ultraviolet radiation, giving way rapidly to a more mildly reducing atmosphere of carbon dioxide and nitrogen. Estimations of O2 produced from the photolysis of water vapor prior to the emergence of photosynthesis range from less than 10 to the -14th to 0.1 times the present atmospheric level, indicating the need for further research. A series of photochemical models of increasing complexity has been developed to study the evolution of atmospheric ozone taking into account reactions with O atoms, hydrogen oxides, nitrogen oxides, and chlorine as well as vertical transport, temperature and tropospheric chemistry so that the total content and vertical distribution of O3 may be determined for a specified level of paleoatmospheric O2.
Document ID
19820049746
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Levine, J. S.
(NASA Langley Research Center Atmospheric Environmental Sciences Div., Hampton, VA, United States)
Date Acquired
August 10, 2013
Publication Date
May 1, 1982
Publication Information
Publication: Journal of Molecular Evolution
Volume: 18
Subject Category
Geophysics
Accession Number
82A33281
Distribution Limits
Public
Copyright
Other

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