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Mars Atmospheric CO2 Condensation Above the North and South Poles as Revealed by Radio Occultation, Climate Sounder, and Laser Ranging ObservationsWe study the condensation of CO2 in Mars atmosphere using temperature profilesretrieved from radio occultation measurements from Mars Global Surveyor (MGS) as wellas the climate sounding instrument onboard the Mars Reconnaissance Orbiter (MRO),and detection of reflective clouds by the MGS Mars Orbiter Laser Altimeter (MOLA). Wefind 11 events in 1999 where MGS temperature profiles indicate CO2 condensation andMOLA simultaneously detects reflective clouds. We thus provide causal evidence thatMOLA non-ground returns are associated with CO2 condensation, which strongly indicatestheir nature being CO2 clouds. The MGS and MRO temperature profiles together revealthe seasonal expansion and shrinking of the area and the vertical extent of atmosphericsaturation. The occurrence rate of atmospheric saturation is maximized at high latitudes inthe middle of winter. The atmospheric saturation in the northern polar region exhibits moreintense seasonal variation than in the southern polar region. In particular, a shrinking ofsaturation area and thickness from LS 270 to 300 in 2007 is found; this is probablyrelated to a planet-encircling dust storm. Furthermore, we integrate the condensation areaand the condensation occurrence rate to estimate cumulative masses of CO2 condensatesdeposited onto the northern and southern seasonal polar caps. The precipitation flux isapproximated by the particle settling flux which is estimated using the impulse responses ofMOLA filter channels. With our approach, the total atmospheric condensation mass canbe estimated from these observational data sets with average particle size as the onlyfree parameter. By comparison with the seasonal polar cap masses inferred from thetime-varying gravity of Mars, our estimates indicate that the average condensate particleradius is 822 mm in the northern hemisphere and 413 mm in the southern hemisphere.Our multi-instrument data analysis provides new constraints on modeling the global climateof Mars.
Document ID
20140005989
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Hu, Renyu
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Cahoy, Kerri
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Zuber, Maria T.
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Date Acquired
May 20, 2014
Publication Date
July 1, 2012
Publication Information
Publication: Journal of Geophysical Research
Publisher: Journal of Geophysical Research
Volume: 117
Issue: E7
Subject Category
Meteorology And Climatology
Report/Patent Number
GSFC-E-DAA-TN9300
Funding Number(s)
CONTRACT_GRANT: NNX09AM53G
CONTRACT_GRANT: NNX11AP47H
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
MOLA
Mars
poles
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