Where the Wind Blows
Where the Wind Blows
ESP_063901_1710  Science Theme: Aeolian Processes
Sand dunes commonly form when particles that are being moved around by the wind find a natural barrier to accumulate and build a hill-like formation. Scientists study dunes because their shape and size can give us valuable information about the wind directions and speeds in current and past climates.

For instance, barchan dunes are crescent-shaped, and they form when the wind blows mainly from one direction (perpendicular to the crescent long edge). On the other hand, “star” dunes have three or more “arms,” and form in environments that that are affected by multiple wind directions. Our image shows an area on Mars with both star and barchan dunes next to each other. This implies that wind directions have changed with time, or that the surrounding landscape is creating complex wind patterns.

Scientists can study HiRISE images collected over time of the same dunes to observe whether they are moving or not, and if so, how fast. By observing multiple dune systems over many seasons, we can get a better picture of wind regimes on Mars and possibly how they have evolved with time.

Written by: M. Ramy El-Maarry (narration: Tre Gibbs)  (1 April 2020)
Acquisition date
14 March 2020

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
260.7 km (162.0 miles)

Original image scale range
26.2 cm/pixel (with 1 x 1 binning) so objects ~79 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

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

Solar longitude
166.2°, Northern Summer

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  18.3°
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

Black and white
map-projected   (394MB)

IRB color
map-projected   (234MB)

Black and white
map-projected  (157MB)
non-map           (244MB)

IRB color
map projected  (50MB)
non-map           (205MB)

Merged IRB
map projected  (102MB)

Merged RGB
map-projected  (96MB)

RGB color
non map           (206MB)
10K (TIFF)

B&W label
Color label
Merged IRB label
Merged RGB label
EDR products

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

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.