HiRISE | These Are Not the Dunes You’re Looking For (ESP_082871

NASA/JPL-Caltech/UArizona

These Are Not the Dunes You’re Looking For
ESP_082871_1240 Science Theme: Aeolian Processes

Lower resolution imaging has been extremely useful in selecting targets, but occasionally is off the mark. HiRISE takes some of its images from a global list of sand dunes that was based on some of these lower resolution data.

In this picture, we discover that the dark bands thought to be sand dunes are instead bands of surface boulders. The bouldery area looks dark at lower resolution because these rocks cast small shadows. We think the bouldery bands are caused by the removal of finer-grained material. Why is fine material removed in bands? That’s harder to explain, but might be related to the topography just off the edge of the image setting up atmospheric turbulence with a specific length scale.

Written by: Shane Byrne (24 June 2024)

Acquisition date
31 March 2024

Local Mars time
15:55

Latitude (centered)
-55.673°

Longitude (East)
308.034°

Spacecraft altitude
249.1 km (154.8 miles)

Original image scale range
49.8 cm/pixel (with 2 x 2 binning) so objects ~149 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
0.3°

Phase angle
57.5°

Solar incidence angle
58°, with the Sun about 32° above the horizon

Solar longitude
227.3°, Northern Autumn

For non-map projected images
North azimuth: 97°
Sub-solar azimuth: 22.1°

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   (174MB)

IRB color
map-projected   (59MB)

JP2 EXTRAS
Black and white
map-projected (78MB)
non-map           (141MB)

IRB color
map projected (26MB)
non-map           (65MB)

Merged IRB
map projected (172MB)

Merged RGB
map-projected (166MB)

RGB color
non map           (62MB)

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.