Frosty Gullies
NASA/JPL-Caltech/UArizona
Frosty Gullies
ESP_037137_1360  Science Theme: Mass Wasting Processes
HiRISE monitoring has shown that gully formation on Mars occurs in winter and early spring in times and places with frost on the ground.

This image was acquired in late winter, and the frost or ice (visible as white areas) persists only on the south-facing slopes that have received little direct sunlight to this date.

Ridges between gully alcoves that get more light are reddish and largely free of frost. New gully activity isn’t obvious in this image. There may be a delicate balance: in some years the frost (up to approximately 1 meter thick) will trigger avalanches, but not in most years. This frost consist of mostly carbon dioxide (dry ice), but includes small amounts of water ice as well.

Written by: Alfred McEwen (audio: Tre Gibbs)  (30 July 2014)
 
Acquisition date
29 June 2014

Local Mars time
15:47

Latitude (centered)
-43.427°

Longitude (East)
314.735°

Spacecraft altitude
254.3 km (158.1 miles)

Original image scale range
51.4 cm/pixel (with 2 x 2 binning) so objects ~154 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
7.8°

Phase angle
81.4°

Solar incidence angle
75°, with the Sun about 15° above the horizon

Solar longitude
153.3°, Northern Summer

For non-map projected images
North azimuth:  96°
Sub-solar azimuth:  38.1°
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   (241MB)

IRB color
map-projected   (126MB)

JP2 EXTRAS
Black and white
map-projected  (83MB)
non-map           (141MB)

IRB color
map projected  (31MB)
non-map           (146MB)

Merged IRB
map projected  (273MB)

Merged RGB
map-projected  (245MB)

RGB color
non map           (131MB)
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-Caltech/UArizona

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.