Changing Dust Devil Tracks and Sand Streaks in Noachis Terra
NASA/JPL-Caltech/UArizona
Changing Dust Devil Tracks and Sand Streaks in Noachis Terra
ESP_030014_1245  Science Theme: Aeolian Processes
Sand dunes on Mars are studied for many reasons. Recent investigations have focused on dune and ripples movement.

In this observation, we look at dunes within a crater in Noachis Terra. Zooming in to one of these areas (and here is the context image) we see the edges of two dunes separated by a field of ripples and rocks. We can compare this area to another image taken two Mars years ago. In the older image, there are many dark wispy features that cover the dunes. These are dust devil tracks, which formed when vortices removed a thin layer of dust off the surface, revealing a darker substrate.

In addition, there are dark sand streaks extending westward from the eastern dune. Blinking between these images shows that virtually all traces of the dust devil tracks and dark streaks have disappeared in the two Mars years. There is also little evidence for dune or ripple movement (however, these images have not yet been orthorectified for a detailed analysis).

In this region, it is likely that dust is periodically deposited and then removed off the dunes. The presence of dust may shield the dunes and ripples from significant movement, such that the observed changes are but thin layers of dust being removed and minor sand streaks that blow off the dunes.

Written by: Nathan Bridges (audio by Tre Gibbs)  (16 January 2013)

This is a stereo pair with ESP_030080_1245.
 
Acquisition date
21 December 2012

Local Mars time
15:33

Latitude (centered)
-55.125°

Longitude (East)
26.825°

Spacecraft altitude
249.5 km (155.0 miles)

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25.8 cm/pixel (with 1 x 1 binning) so objects ~77 cm across are resolved

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25 cm/pixel and North is up

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14.0°

Phase angle
66.8°

Solar incidence angle
54°, with the Sun about 36° above the horizon

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229.4°, Northern Autumn

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POSTSCRIPT
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. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.