The Icy Surface of the North Polar Cap
NASA/JPL/University of Arizona
The Icy Surface of the North Polar Cap
ESP_036867_2655  Science Theme: Polar Geology
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At Mars’ North Pole is a dome of icy layers ranging up to 2 kilometers thick, roughly analogous to the Earth’s ice caps in Greenland or Antarctica.

Although not visible here, the dome is characterized by incised spiraling troughs that reveal sequences of layers thought to reflect varying climate conditions over the time they were originally deposited. This image is of an area on the top surface of the polar dome between the troughs — vast, generally smooth, flat plains composed of a thin layer of very pure water ice. This image also shows that this thin ice layer has a rough texture, composed of knobs, ridges, and depressions on the scale of 1 - 10 meters.

This texture is only beginning to be studied with the high-resolution capabilities of HiRISE — the details of the texture varies around the polar cap, but the causes of the variation are not yet clear. This image has two particularly interesting features. One is that the surface dips into a depression towards the southwest, where the texture of the ice surface appears to change. The other is that there is a fracture or chain of pits in the southeast, which is a rare feature.

The brightness, composition, texture, and small-scale features of this ice layer that covers most of the polar dome are important as they influence the local energy balance (such the amount of sunlight reflected and absorbed), which in turn influences polar-wide climate and the stability of ice.

Written by: Patrick Russell  (16 July 2014)
 
Acquisition date
08 June 2014

Local Mars time
13:06

Latitude (centered)
85.594°

Longitude (East)
77.357°

Spacecraft altitude
317.4 km (197.2 miles)

Original image scale range
31.8 cm/pixel (with 1 x 1 binning) so objects ~95 cm across are resolved

Map projected scale
25 cm/pixel

Map projection
Polarstereographic

Emission angle
0.1°

Phase angle
70.9°

Solar incidence angle
71°, with the Sun about 19° above the horizon

Solar longitude
142.6°, Northern Summer

For non-map projected images
North azimuth:  128°
Sub-solar azimuth:  323.6°
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non-map           (452MB)

IRB color
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non-map           (386MB)

Merged IRB
map projected  (247MB)

Merged RGB
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RGB color
non map           (328MB)
ADDITIONAL INFORMATION
B&W label
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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.