HR: 1330h
AN: P42A-0418    [PDF]
TI: Seasonal Variations of Albedo and Temperature of the North Polar Cap of Mars.
AU: * Mahoney, S A
EM: mahoneys@scsr.nevada.edu
AF: Geological Sciences MS 172, Univesity of Nevada, Reno, NV 89557 United States
AU: Calvin, W M
EM: wcalvin@unr.edu
AF: Geological Sciences MS 172, Univesity of Nevada, Reno, NV 89557 United States
AU: Titus, T N
EM: ttius@usgs.gov
AF: U.S. Geological Survey, 2255 N. Gemini Dr., Flagstaff, AZ 86001 United States
AB: Previous observations of Viking and MOC have suggested that the north polar residual ice cap exhibits albedo variations between Mars years and within the summer seasons. Our work makes use of the Mars Global Surveyor-Thermal Emission Spectrometer (MGS-TES) data sets. TES can supplement these initial observations, since it provides calibrated albedo, temperature and repeat coverage of the poles, allowing for detailed seasonal coverage. The TES data of the northern summer season allows us to observe the albedo and temperature evolution and explore how that variability relates to climate and atmospheric models. While TES provides excellent seasonal coverage the spatial footprint is 3x6 km eliminating the level of detail somewhat. We will present seasonal and interannual variations of temperature and albedo as observed by TES. To date we have explored variations in the first northern summer, which were taken from March to May of 1999. The first part of the season has a large high albedo area from approximately -60 to 60 W and 80 to 85 N. This area decreases significantly in albedo during the season. Some outlying valleys of the cap appear to show some brightening later in the season from 30 to 90 W and 85 N. This area may have been interpreted in the past as brightening albedo but it appears to be only relative brightening compared to the larger area that has since decreased in albedo. We see an anomalous bright spot throughout the season at -30 W and 88 N. We also see some bright outliers later in the season at 180 W and 75 N,which is near Kovolev, and 10 to 15 W and 78 N. The temperature of the cap is shown to have a stronger variation at the beginning of the season and towards the end it has a more homogeneous temperature. There appears to be a 50 % decrease in temperature extremes from the beginning of the season to the end. Through comparisons with MOC and MOLA data we hope to observe where topography and smaller scale albedo variations may be affecting our measurements. Acknowledgments: This material is based on work currently supported by NASA under the MDAP program, Grant: NAG5-12223 to the University of Nevada, Reno.
DE: 5462 Polar regions
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting