Dunes on the Move
Dunes on the Move
ESP_027864_2295  Science Theme: Aeolian Processes
HiRISE has been carrying out a dedicated survey of sand dunes on Mars, determining whether and how fast the dunes move by observing repeatedly at intervals of Martian years. More than 60 sites have been monitored so far, showing that sand dunes from the equator to the poles are advancing at rates of up to 1 meter per Martian year.

This image shows a variety of different dune types in southern Lyot Crater in the northern lowlands. Transverse dunes to the west grade into longitudinal dunes downwind to the east and barchans to the south, possibly because of local winds channeled by topography in the impact basin. This image was intended to match the approximate illumination and viewing conditions of an earlier HiRISE observation that was made two Martian years earlier, in August 2008.

Detailed comparison of the two images shows movement on many of the dunes during this interval of nearly four Earth years. Here is an animation showing changes on one of the small barchans in the south of the dune field (about 100 meters across). Winds from the west (left) have shifted the small ripples up the back of the dune towards the east. Sand has blown over the crest of the dune, cascaded down the steep slip face, and accumulated along the base of the slip face in the lee of the dune. In this way, the small dune advances slowly downwind.

Other images also show dune activity in this latitude band, adding to a growing suspicion that dunes are on the move everywhere on Mars, faster in some places than others.

Written by: Paul Geissler (narration: Tre Gibbs)  (1 August 2012)
Acquisition date
06 July 2012

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
306.5 km (190.5 miles)

Original image scale range
from 30.8 cm/pixel (with 1 x 1 binning) to 61.7 cm/pixel (with 2 x 2 binning)

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
50°, with the Sun about 40° above the horizon

Solar longitude
135.4°, Northern Summer

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North azimuth:  98°
Sub-solar azimuth:  343.6°
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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’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.