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Ammonia photolysis and the greenhouse effect in the primordial atmosphere of the earthPhotochemical calculations indicate that in the prebiotic atmosphere of earth ammonia would have been irreversibly converted to N2 in less than 40 years if the ammonia surface mixing ratio were no more than 0.0001. However, if a continuous outgassing of ammonia were maintained, radiative-equilibrium calculations indicate that a surface mixing ratio of ammonia of 0.0001 or greater would provide a sufficient greenhouse effect to keep the surface temperature above freezing. With a 0.0001 mixing ratio of ammonia, 60% to 70% of the present-day solar luminosity would be adequate to maintain surface temperatures above freezing. A lower limit to the time constant for accumulation of an amount of nitrogen equivalent to the present day value is 10 my if the outgassing were such as to provide a continuous surface mixing ratio of ammonia of at least 0.00001.
Document ID
19790043902
Document Type
Reprint (Version printed in journal)
Authors
Kuhn, W. R.
(Michigan Univ. Ann Arbor, MI, United States)
Atreya, S. K.
(Michigan, University Ann Arbor, Mich., United States)
Date Acquired
August 9, 2013
Publication Date
January 1, 1979
Publication Information
Publication: Icarus
Volume: 37
Subject Category
Geophysics
Funding Number(s)
CONTRACT_GRANT: NSG-7404
CONTRACT_GRANT: NSG-7308
Distribution Limits
Public
Copyright
Other
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