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Published April 2000 | public
Journal Article

The 1997 Spring Regression of the Martian South Polar Cap: Mars Orbiter Camera Observations

Abstract

The Mars Orbiter cameras (MOC) on Mars Global Surveyor observed the south polar cap of Mars during its spring recession in 1997. The images acquired by the wide angle cameras reveal a pattern of recession that is qualitatively similar to that observed by Viking in 1977 but that does differ in at least two respects. The 1977 recession in the 0° to 120° longitude sector was accelerated relative to the 1997 observations after L_S = 240°; the Mountains of Mitchel also detached from the main cap earlier in 1997. Comparison of the MOC images with Mars Orbiter Laser Altimeter data shows that the Mountains of Mitchel feature is controlled by local topography. Relatively dark, low albedo regions well within the boundaries of the seasonal cap were observed to have red-to-violet ratios that characterize them as frost units rather than unfrosted or partially frosted ground; this suggests the possibility of regions covered by CO_2 frost having different grain sizes.

Additional Information

© 2000 Academic Press. Received February 22, 1999; revised June 21, 1999. This research was partially supported by a Mars Global Surveyor Participating Scientist Grant and by a Mars Global Surveyor Data Analysis Grant from Mars Exploration directorate.

Additional details

Created:
August 22, 2023
Modified:
October 20, 2023