Defrosting Dunes within Chasma Boreale
NASA/JPL/University of Arizona
Defrosting Dunes within Chasma Boreale
ESP_052418_2650  Science Theme: Seasonal Processes
twitter  •  tumblr

HICLIP
1080p (MP4)
Audio (MP3)

WALLPAPER
800
1024
1152
1280
1440
1600
1920
2048
2560
2736
2880
4500
4K
8K

HIFLYER
PDF (11 x 17)

HISLIDES
PowerPoint
Keynote
PDF

This image shows a dune field in Chasma Boreale, which is a large trough that cuts into the North Polar ice cap. Some of the dunes in this image are quite long and sinuous with a slight bulge at one end like a “head,” giving it the appearance of a snake.

However, most of the dunes visible here are of the type referred to as “barchan,” which are characterized by their crescent shape. For these types of dunes, the “mouth” of the crescent points in the downwind direction, indicating that the winds are traveling east-west. The diverse dune morphologies here suggest that the wind-direction changes over a very small area.

Because Mars has a similar axial tilt to Earth, it also experiences seasons. When we took this image, Mars was in late spring. At this time of year, the dunes in this image are almost completely covered by frost. But this will soon change! Small portions of the underlying dark basaltic sands of these dunes are becoming increasingly visible with the active removal of their seasonal coating of ice. A look at a series of images demonstrates the the transition from early to late spring, marked by defrosting and the gradual growth of dark spots. By summer, the dunes will be defrosted, and will appear completely black.

Written by: Eric Pilles, Livio Tornabene, Matthew Bourassa and Radu Capitan (audio: Tre Gibbs)  (23 October 2017)
 
Acquisition date
01 October 2017

Local Mars time:
12:55

Latitude (centered)
84.855°

Longitude (East)
333.879°

Spacecraft altitude
319.2 km (199.5 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
Polarstereographic

Emission angle:
0.3°

Phase angle:
61.9°

Solar incidence angle
62°, with the Sun about 28° above the horizon

Solar longitude
68.5°, Northern Spring

For non-map projected images
North azimuth:  121°
Sub-solar azimuth:  314.3°
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   (747MB)

IRB color
map-projected   (424MB)

JP2 EXTRAS
Black and white
map-projected  (363MB)
non-map           (302MB)

IRB color
map projected  (123MB)
non-map           (261MB)

Merged IRB
map projected  (184MB)

Merged RGB
map-projected  (170MB)

RGB color
non map           (226MB)
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.