Martian Barchans
NASA/JPL/University of Arizona
Martian Barchans
ESP_014404_1765  Science Theme: Aeolian Processes
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Barchan dunes are common on both Earth and Mars. These dunes are very distinctive in shape, and are important because they can tell scientists about the environment in which they formed.

Barchans form in wind regimes that blow in one dominant direction. The ridged arcs of sand that define the barchan dunes end in horns that point downwind. Sand is transported up the broad, relatively shallow windward slopes and once it overtops the dune crest, the sand falls down a shorter steeper slope between the horns, known as the slip face. Over time, the barchans migrate downwind, following their horns. (The subimage refers to the non-map projected version of the image.)

This HiRISE image shows an example of several barchans merging to form an even larger barchan dune. This can happen through a variety of circumstances, such as when smaller, faster dunes collide with larger, slower-moving dunes that absorb them, resulting in single, larger dunes. The distance between the merging horns of the large dune in this highlighted region is a little over 500 meters (about 1600 feet).

Written by: Andrea Philippoff   (11 December 2009)

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Acquisition date
22 August 2009

Local Mars time:
14:17

Latitude (centered)
-3.271°

Longitude (East)
307.617°

Range to target site
268.3 km (167.7 miles)

Original image scale range
26.8 cm/pixel (with 1 x 1 binning) so objects ~81 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle:
5.0°

Phase angle:
30.7°

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

Solar longitude
325.8°, Northern Winter

North azimuth:
97°

Sub-solar azimuth:
345.8°
JPEG
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

JP2
Black and white
map-projected   (703MB)

IRB color
map-projected   (289MB)

JP2 EXTRAS
Black and white
map-projected  (302MB)
non-map           (407MB)

IRB color
map projected  (103MB)
non-map           (294MB)

Merged IRB
map projected  (157MB)

Merged RGB
map-projected  (147MB)

RGB color
non map           (293MB)
ADDITIONAL INFORMATION
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products
HiView

NB
IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images



USAGE POLICY
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.