Disappearing Dunes
NASA/JPL/University of Arizona
Disappearing Dunes
PSP_007726_2565  Science Theme: Aeolian Processes
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More than 10 percent of the surface area north of 65 degrees North on Mars has some type of cover by windblown sand dunes. This HiRISE image shows large barchan (crescent-shaped), barchanoid and some smaller dome-shaped dunes.

The image is of a location where the first significant change to sand dunes was reported on Mars (Bourke et al, 2008). That study used a time series of MOC images taken over a period of three Mars years and showed that two 20 meter-wide dome dunes disappeared and a third shrank by an estimated 15 percent. The HiRISE image confirms that the dune forms no longer exist but, interestingly, suggests that the sediment removal is ongoing as the third dune has been reduced in volume.

Other, larger dunes in the location do not show apparent change: more time or more precise measurements to display evidence of change is needed. Alternately, the sediment in the larger dunes may be unavailable for transport at the present time due to induration. Nevertheless, the change observed in the small dome dunes indicates that not all dunes on Mars are effectively stabilized and immobile.

Written by: Mary Bourke   (24 April 2008)

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Acquisition date
20 March 2008

Local Mars time:
14:10

Latitude (centered)
76.182°

Longitude (East)
95.300°

Range to target site
318.0 km (198.8 miles)

Original image scale range
63.6 cm/pixel (with 2 x 2 binning) so objects ~191 cm across are resolved

Map projected scale
50 cm/pixel

Map projection
Polarstereographic

Emission angle:
2.8°

Phase angle:
62.5°

Solar incidence angle
60°, with the Sun about 30° above the horizon

Solar longitude
47.6°, Northern Spring

North azimuth:
103°

Sub-solar azimuth:
318.7°
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RGB: red-green-blue
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All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:
NASA/JPL/University of Arizona



Postscript
For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.