Circular Sand Dunes
NASA/JPL-Caltech/UArizona
Circular Sand Dunes
ESP_076510_2230��Science Theme:�Seasonal Processes
Sand dunes of many shapes and sizes are common on Mars. In this example, the dunes are almost perfectly circular, which is unusual.

They are still slightly asymmetrical, with steep slip faces on the south ends. This indicates that sand generally moves to the south, but the winds may be variable.

This is part of a series of images to monitor how frost disappears in the late winter; this observation appears to be free of frost. A previous image shows when the surface was covered by frost.

Written by: Alfred McEwen (narration: Tre Gibbs)��(2 March 2023)
Acquisition date
22 November 2022

Local Mars time
14:16

Latitude (centered)
42.505�

Longitude (East)
67.076�

Spacecraft altitude
298.2 km (185.3 miles)

Original image scale range
30.3 cm/pixel (with 1 x 1 binning) so objects ~91 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
8.5�

Phase angle
53.1�

Solar incidence angle
59�, with the Sun about 31� above the horizon

Solar longitude
342.3�, Northern Winter

For non-map projected images
North azimuth:��96�
Sub-solar azimuth:��316.1�
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�� (751MB)

IRB color
map-projected�� (429MB)

JP2 EXTRAS
Black and white
map-projected� (316MB)
non-map���������� (407MB)

IRB color
map projected� (110MB)
non-map���������� (309MB)

Merged IRB
map projected� (194MB)

Merged RGB
map-projected� (186MB)

RGB color
non map���������� (299MB)
BONUS
4K (TIFF)
8K (TIFF)
10K (TIFF)

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-Caltech/UArizona

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.