Dunes and Polygons
Dunes and Polygons
PSP_008839_2575  Science Theme: Seasonal Processes
At high northern latitudes, shallow troughs in the ice-rich ground form polygonal patterns. The polygons form over many years as the near-surface ice contracts and expands seasonally.

On top of this patterned ground in this image are dunes. Loose sand and dust are blown across the hard-cemented surface until collecting and forming a dune. Streaks of dust are visible in this color subimage coming from the horns of the dunes, while the higher portion of the dune blocks the dust from being blown across the surface.

Small ripples are also visible, and the small bright spots are the remnants of the seasonal carbon dioxide polar cap that coats this area in the winter.

Written by: Candy Hansen  (30 July 2008)
Acquisition date
15 June 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
317.3 km (197.2 miles)

Original image scale range
31.9 cm/pixel (with 1 x 1 binning) so objects ~96 cm across are resolved

Map projected scale
25 cm/pixel

Map projection

Emission angle

Phase angle

Solar incidence angle
55°, with the Sun about 35° above the horizon

Solar longitude
85.6°, Northern Spring

For non-map projected images
North azimuth:  105°
Sub-solar azimuth:  324.0°
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   (1570MB)

IRB color
map-projected   (682MB)

Black and white
map-projected  (1007MB)
non-map           (719MB)

IRB color
map projected  (478MB)
non-map           (584MB)

Merged IRB
map projected  (408MB)

Merged RGB
map-projected  (389MB)

RGB color
non map           (566MB)
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.