Linear Dunes in the North Polar Region
Linear Dunes in the North Polar Region
PSP_009739_2580  Science Theme: Aeolian Processes
This observation shows linear dunes in the north polar region of Mars. Linear or longitudinal sand dunes are elongated, sharp crested ridges that are typically separated by a sand-free surrounding surface.

These features form from bi-directional winds and extend parallel to the net wind direction. In this case, the net wind direction appears to be from the west-southwest. Linear sand dunes are found in many different locations on Earth and commonly occur in long parallel chains with regular spacing.

Superimposed on the surface of the linear dunes are smaller secondary dunes or ripples. This is commonly observed on terrestrial dunes of this size as well. Polygons formed by networks of cracks cover the substrate between the linear dunes and may indicate that ice-rich permafrost (permanently frozen ground) is present or has been present geologically recently in this location.

Written by: Maria Banks  (22 October 2008)
Acquisition date
24 August 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
317.9 km (197.5 miles)

Original image scale range
from 31.8 cm/pixel (with 1 x 1 binning) to 63.6 cm/pixel (with 2 x 2 binning)

Map projected scale
25 cm/pixel

Map projection

Emission angle

Phase angle

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

Solar longitude
117.1°, Northern Summer

For non-map projected images
North azimuth:  104°
Sub-solar azimuth:  326.4°
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IRB color
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Merged IRB
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Merged RGB
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RGB color
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Black and white
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IRB color
map-projected   (911MB)

Black and white
map-projected  (919MB)
non-map           (553MB)

IRB color
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non-map           (666MB)

Merged IRB
map projected  (300MB)

Merged RGB
map-projected  (281MB)

RGB color
non map           (659MB)
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.