PIA17646: Migrating and Static Sand Ripples on Mars
Target Name: Mars
Is a satellite of: Sol (our sun)
Mission: Mars Reconnaissance Orbiter (MRO)
Spacecraft: Mars Reconnaissance Orbiter (MRO)
Instrument: HiRISE
Product Size: 2880 x 1800 pixels (width x height)
Produced By: University of Arizona/HiRise-LPL
Other Information: Other products from image ESP_032616_1275
Full-Res TIFF: PIA17646.tif (15.56 MB)
Full-Res JPEG: PIA17646.jpg (820.1 kB)

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Original Caption Released with Image:

Having operated at Mars for more than seven years, MRO and the HiRISE camera continue to make new discoveries. One of these is that many sand dunes and ripples are moving, some at rates of several meters per year.

In this observation, a dune field in a Southern hemisphere crater was observed approximately one Mars year apart, first on 2 September 2011 and then again on 11 July 2013 (a year on Mars is 687 Earth days). By taking images at the same time of year, solar illumination angles are the same, so that subtle apparent changes can be linked to true displacement on the surface and not artifacts.

In these two images, there is little distortion (a digital elevation model would remove more distortion). Here, we focus on the southern and northern part of two adjacent dunes. With an animated image, the displacement of ripples on the dunes relative to nearby rocks and dark ripples are clearly visible. It seems that the ripples on the southern dune are moving northeast, while those on the northern dune are moving west, indicating complex winds in this area. The static dark ripples may be composed of larger grains than those in the dunes and are therefore harder to move.

In most areas of Mars, darker-toned ripples are more mobile than lighter ones. This area is different, demonstrating that continued imaging of the Martian surface results in new findings and revisions of ideas.

This is a stereo pair with ESP_032748_1275.

HiRISE is one of six instruments on NASA's Mars Reconnaissance Orbiter. The University of Arizona, Tucson, operates the orbiter's HiRISE camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Science Mission Directorate, Washington.

Image Credit:
NASA/JPL-Caltech/Univ. of Arizona

Image Addition Date:
2013-08-28