Seasonal Variations of Snow

• Main Authors: Depth On Mars, David E. Smith, Maria T. Zuber, Gregory A. Neumann
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: North Pole; South Pole; Ice cap; South pole
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.61.4083; http://ltpwww.gsfc.nasa.gov/tharsis/smith_snow.pdf

or, and surface frost reaches mid-latitudes in late winter (3). In early spring, as the surface receives more sunlight, surficial CO 2 sublimates back into the atmosphere, causing the frost line to retreat to high latitudes. The elevation of the north pole of Mars is 6 km lower than the south pole (4, 5). In the north during the summer, the temperature rises above the CO 2 condensation temperature, and dry ice frost deposited during the previous winter sublimes away, revealing a residual H 2 O ice cap (6, 7). In contrast, the southern polar region is colder and has a lower atmospheric pressure, and as a consequence its surface veneer of CO 2 does not completely sublime. A residual dry ice surface is observed even in summer (8), although observations of atmospheric water vapor during some years (9, 10) have been cited as evidence for at least some surficial H 2 O(11). Both polar regions contain layered terrains that are characterized by about 3 km of relief (5, 12) and are believed to