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The obliquity of Mars and 'climate friction'A mathematical theory is presented which explains the increase of the mean obliquity of Mars over geologic time due to the so called 'climate friction' (i.e., the climatic changes associated with obliquity oscillations of Mars). The theory is compared with a 10 m.y. numerical integration of the equations performed for a hypothetically large amount of climate friction for two cases of the obliquity oscillations: (1) a single sinusoid and (2) a sum of three sinusoids. The theory and numerics agree for both cases within about 12 percent on the size of the secular increase in obliquity. One possible mechanism of climate friction investigated is 'postglacial rebound' on Mars. According to this theory, giant polar caps form when the obliquity is low, and slowly squeeze out an equatorial bulge. When the obliquity is high, the caps disappear, but the bulge takes some time to collapse, due to mantle viscosity, causing it to oscillate out of phase with the obliquity oscillations. This causes a secular increase in the average obliquity.
Document ID
19930060258
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Rubincam, David P.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 16, 2013
Publication Date
June 25, 1993
Publication Information
Publication: Journal of Geophysical Research
Volume: 98
Issue: E6
ISSN: 0148-0227
Subject Category
Lunar And Planetary Exploration
Accession Number
93A44255
Distribution Limits
Public
Copyright
Other

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