Evolution of North Polar Dunes
NASA/JPL/UArizona
Evolution of North Polar Dunes
PSP_009233_2535  Science Theme: Aeolian Processes
This small unnamed crater is adjacent to the North Polar Erg and contains a fascinating dune field. Scientists are interested in the source of the dunes in the crater and the evolution of the dune field's circular shape.

Wind transports material and shapes the dunes; the dominant wind comes from a westerly-southwesterly direction and forms barchans (crescent-shaped) and barchanoid dunes. Secondary winds also play a role in shaping the dunes. This can be seen in the southern part of the dune field where the barchans transition into transverse dunes. On the northern edge of the dune field are opposite facing barchans formed by winds from the northeast.

The circular shape of this dune field is interesting because the outer dunes reflect changing winds whereas the central dunes do not. This could indicate several distinct stages in the formation of the dune field. On top of the dark dunes are tiny ripples similar to those seen on top of sand dunes on Earth. It is likely that these dune ripples are active, as shown by avalanches (grainflow) from the crest of the dunes.




Written by: Circe Verba  (3 September 2008)
 
Acquisition date
15 July 2008

Local Mars time
14:50

Latitude (centered)
73.533°

Longitude (East)
348.233°

Spacecraft altitude
319.1 km (198.3 miles)

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

Map projected scale
25 cm/pixel

Map projection
Polarstereographic

Emission angle
1.0°

Phase angle
53.0°

Solar incidence angle
54°, with the Sun about 36° above the horizon

Solar longitude
99.2°, Northern Summer

For non-map projected images
North azimuth:  100°
Sub-solar azimuth:  328.3°
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   (718MB)

IRB color
map-projected   (292MB)

JP2 EXTRAS
Black and white
map-projected  (272MB)
non-map           (310MB)

IRB color
map projected  (63MB)
non-map           (225MB)

Merged IRB
map projected  (173MB)

Merged RGB
map-projected  (167MB)

RGB color
non map           (216MB)
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/University of Arizona

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.