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Color Reveals Translucent Seasonal Ice
12.11.07
Color Reveals Translucent Seasonal Ice
+ Higher resolution

In a region near the south pole of Mars translucent carbon dioxide ice covers the ground seasonally. For the first time we can "see" the translucent ice by the affect it has on the appearance of the surface below.

Dark fans of dust (1) from the surface drape over the top of the seasonal ice. The surface would be the same color as the dust except that the seasonal ice affecting its appearance. Bright bluish streaks are frost that has re-crystallized from the atmosphere.

Color Reveals Translucent Seasonal Ice
(1) › Visit HiRISE site for higher resolution image (tiff)

Sunlight can penetrate through the seasonal layer of translucent ice to warm the ground below. That causes the seasonal ice layer to sublime (evaporate) from the bottom rather than the top.

Observation Geometry
Image PSP_002942_0935 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 13-Mar-2007. The complete image is centered at -86.4 degrees latitude, 99.2 degrees East longitude. The range to the target site was 245.4 km (153.4 miles). At this distance the image scale is 49.1 cm/pixel (with 2 x 2 binning) so objects ~147 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel . The image was taken at a local Mars time of 06:41 PM and the scene is illuminated from the west with a solar incidence angle of 82 degrees, thus the sun was about 8 degrees above the horizon. At a solar longitude of 199.6 degrees, the season on Mars is Northern Autumn.

Image Credit: NASA/JPL/University of Arizona