Marching Dust Devils
NASA/JPL/University of Arizona
Marching Dust Devils
ESP_042201_1715  Science Theme: Seasonal Processes

HICLIP

1080p (MP4)
720p (MP4)
Listen to the text

WALLPAPER

800  1024
1152  1280
1440  1600
1920  2048
2560  2880

HIFLYER

PDF, 11 x 17 in

HISLIDES

PowerPoint
Keynote
PDF
On an early fall afternoon in Ganges Chasma (Valles Marineris), we managed to capture a cluster of 8 dust devils, five of them in the enhanced color strip. They’re together on a dark sandy surface that tilts slightly to the north, towards the Sun.

Both of these factors help warm the surface and generate convection in the air above. The surface is streaked with the faint tracks of earlier dust devils. A pair of dust devils appears together at top right, spaced only 250 meters apart. These two have quite different morphologies. The bigger one (on the right) is about 100 meters in diameter and is shaped like a doughnut with a hole in the middle. Its smaller companion is more compact and plume-like, but it too has a small hole in the center, where the air pressure is lowest. It may be that the smaller dust devil is younger than the larger one. A row of four dust devils are in the middle of the color strip, separated by about 900 meters from one another.

This image might answer some interesting questions about the behavior of dust devils. Dust devils are theoretically expected to migrate uphill on a sloping surface, or migrate downwind when there is a breeze. Where they are found close together in pairs, they are expected to rotate in opposite directions. HiRISE color observations can be used to determine the direction of rotation and—for fast moving dust devils—the direction of their travel. This is because the different color observations (infrared, red, and blue) are taken at slightly different times. The differences between the earliest color observation and the last tell us about the changes that took place during that time interval.

All this requires careful analysis, but if these dust devils are moving fast enough, and spaced closely enough, these here might display some interesting “social dynamics,” possibly marching together and rotating in alternating directions.

Written by: Paul Geissler   (4 November 2015)

This is a stereo pair with ESP_043190_1715.

Click to share this post on Twitter Click to share this post on Facebook Click to share this post on Google+ Click to share this post on Tumblr
 
Acquisition date
28 July 2015

Local Mars time:
14:39

Latitude (centered)
-8.268°

Longitude (East)
310.786°

Range to target site
267.6 km (167.3 miles)

Original image scale range
53.6 cm/pixel (with 2 x 2 binning) so objects ~161 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection
Equirectangular

Emission angle:
2.9°

Phase angle:
40.4°

Solar incidence angle
43°, with the Sun about 47° above the horizon

Solar longitude
19.5°, Northern Spring

North azimuth:
97°

Sub-solar azimuth:
27.9°
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   (352MB)

IRB color
map-projected   (206MB)

JP2 EXTRAS
Black and white
map-projected  (191MB)
non-map           (204MB)

IRB color
map projected  (97MB)
non-map           (221MB)

Merged IRB
map projected  (417MB)

Merged RGB
map-projected  (376MB)

RGB color
non map           (201MB)
ANAGLYPHS
Map-projected, reduced-resolution
Full resolution JP2 download
Anaglyph details page

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
For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. 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. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.