Of Swirls and Gullies
Of Swirls and Gullies
ESP_021899_1095  Science Theme: Aeolian Processes
The dune gullies at edge of this field and here in this cutout appear active and are anomalous in their location (the high latitudes).

Tracking definitive changes will be useful in comparison with dune gully activity visible in southern mid-latitudes and the northern polar erg. The activity is thought to occur soon after the beginning of the defrosting period.

Perhaps the most striking aspect of this observation are the beautiful swirls of tracks left by dust devils. Like on Earth, dust devils move across the Martian surface, exposing the underlying darker material.

This caption is based on the original science rationale.

Written by: HiRISE Science Team  (2 May 2011)
Acquisition date
29 March 2011

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
249.1 km (154.8 miles)

Original image scale range
25.1 cm/pixel (with 1 x 1 binning) so objects ~75 cm across are resolved

Map projected scale
25 cm/pixel

Map projection

Emission angle

Phase angle

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

Solar longitude
264.0°, Northern Autumn

For non-map projected images
North azimuth:  100°
Sub-solar azimuth:  37.7°
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Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

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.