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Aeronomy of the lower atmosphere of Mars
Author(s) -
Hunten Donald M.
Publication year - 1974
Publication title -
reviews of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.087
H-Index - 156
eISSN - 1944-9208
pISSN - 8755-1209
DOI - 10.1029/rg012i003p00529
Subject(s) - aeronomy , photodissociation , atmospheric sciences , atmosphere (unit) , mars exploration program , ozone , atmosphere of mars , astrobiology , mixing ratio , atmospheric chemistry , environmental science , martian , meteorology , chemistry , photochemistry , physics
Recent models and observations relevant to Martian aeronomy are discussed. The stability of the CO 2 atmosphere against photodissociation into CO and O 2 has finally been accounted for. The basic mechanism is catalysis by odd hydrogen, aided by very rapid downward mixing, photolysis of H 2 O 2 , or some combination. The low abundance of ozone at low latitudes is readily explained, and its higher abundance in cold regions is accounted for by the freezing out of H 2 O, H 2 O 2 , and possibly HO 2 . The system seems likely to be unstable, and major changes of the CO and O 2 abundances may be expected on a time scale of 1 year.