Fans on Ice
NASA/JPL/University of Arizona
Fans on Ice
ESP_011351_0945  Science Theme: Seasonal Processes
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Every southern winter the south polar region of Mars is covered with an approximately 1 meter deep layer of frozen carbon dioxide (dry ice). In the spring, when the sun begins to warm the surface below the translucent ice, gas flow under the ice carries loose dust from the surface up onto the top.

The dust falls to the surface in fans, whose orientation is determined by the direction of the local wind flow. Fans from one source region pointing in multiple directions show how the wind direction has changed. Narrow fans pointing in just one direction are the most recent. Alternatively, the vent from the surface may have re-annealed, such that these fans were formed over a very limited time span.

Written by: Candy Hansen   (18 February 2009)

This is a stereo pair with ESP_011350_0945.

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Acquisition date:27 December 2008 Local Mars time:18:18
Latitude (centered):-85.216° Longitude (East):181.548°
Range to target site:247.4 km (154.6 miles)Original image scale range:99.0 cm/pixel (with 4 x 4 binning) so objects ~297 cm across are resolved
Map projected scale:100 cm/pixelMap projection:Polarstereographic
Emission angle:4.1° Phase angle:86.4°
Solar incidence angle:90°, with the Sun about 0° above the horizon Solar longitude:181.2°, Northern Autumn

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