Dramatic Changes over the South Polar Cap
Dramatic Changes over the South Polar Cap
ESP_058515_0955  Science Theme: Polar Geology
The south polar residual cap of carbon dioxide ice rapidly changes. This image was planned as an almost exact match to the illumination and viewing angles of a previous one we took in August 2009.

The pits have all expanded and merged, and we can just barely see the patterns in the 2009 image compared to this January 2019 picture. The 2009 image is also brighter and bluer, with more seasonal frost and/or less dust over the surface. These images were both taken in late southern summer, but our 2019 picture is slightly later in the Martian season by about two weeks.

This gap allowed for additional loss of frost that might make the surface darker, but there are also year-to-year changes. In particular, there was a near-global dust storm in the summer of 2018 and late southern spring on Mars, and extra deposits of dust would have warmed the surface and promoted even more disappearance of the frost.

Written by: Alfred McEwen (audio: Tre Gibbs)  (1 April 2019)
Acquisition date
19 January 2019

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
245.0 km (152.3 miles)

Original image scale range
24.5 cm/pixel (with 1 x 1 binning) so objects ~74 cm across are resolved

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25 cm/pixel

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Phase angle

Solar incidence angle
74°, with the Sun about 16° above the horizon

Solar longitude
327.1°, Northern Winter

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North azimuth:  121°
Sub-solar azimuth:  58.2°
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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.