HR: 13:40h
AN: P23C-01 INVITED     [Abstracts]
TI: Variation in the Masses of the Seasonal Martian Icecaps
AU: * Smith, D E
EM: David.E.Smith@nasa.gov
AF: NASA/GSFC, Code 690, Greenbelt, MD 20771 United States
AU: Zuber, M T
EM: zuber@mit.edu
AF: MIT, Dept. of Earth, Atmospheric and Planetary Sciences, Cambridge, MA 02139 United States
AB: Since early 1999 through late 2004 the masses of the Martian icecaps have been estimated from the tracking data on the Mars Global Surveyor at approximately 5 day intervals. The masses of the two icecaps were estimated in conjunction with a loosely constrained mass of the atmosphere derived from the atmospheric pressure variations observed by the Viking 2 Lander and the total mass of volatile material was constrained to be constant. The total volatile mass was represented as 3 mass anomalies of finite area, one for each polar cap and a third over the rest of the planet's surface The variation in the cap size as a function of season was derived from the variation in brightness of the cap obtained from MOLA radiometry measurements over the same period. The elevation of the seasonal polar caps was based upon MOLA altimetry measurements of the heights of the caps. The nearly 6 Earth-year period covers approximately 3 Mars years and each polar cap displays annual and semi-annual periods as expected, but also variations that can be well represented by three and four oscillations per Mars year.
DE: 5410 Composition (1060, 3672)
DE: 5416 Glaciation
DE: 5462 Polar regions
SC: Planetary Sciences [P]
MN: Fall Meeting 2005