A Monster Dust Devil Stalks the Martian Landscape
NASA/JPL/University of Arizona

A Monster Dust Devil Stalks the Martian Landscape
ESP_026394_2160  Science Theme: Aeolian Processes
FrançaisDeutschEspañolItalianoGreek


HICLIP

720p (MP4)  
Listen to the text  

WALLPAPER

800  1024  
1152  1280  
1440  1600  
1920  2048  
2560  

HIFLYER

PDF, 11 x 17 in  

HISLIDES

PowerPoint  
Keynote  
PDF  
A dust devil the size of a terrestrial tornado towers above the Martian surface in this late springtime afternoon image of Amazonis Planitia.

Also captured by the Context Camera on MRO, the length of the shadow indicates that the dust plume reached a height of 20 kilometers (12 miles) above the surface! This height refers to the top of the disconnected dust clouds above the plume; the continuous column of dust reached about half that altitude. Despite its gargantuan height, the plume is only 140 meters (140 yards) in diameter, giving it a snake-like appearance that is twisted by high altitude winds, similar to another dust devil spotted recently in this region.

Typical tornadoes on Earth are less than 10 miles tall, while dust devils on our planet seldom reach more than a few hundred yards in height. So, why do we classify this plume as a monster dust devil and not a Martian tornado? Dust devils differ from tornadoes in their energy sources. Dust devils are driven by the heat of the surface, absorbed from sunlight and re-radiated to warm the atmosphere. The warm air rises and spins as it contracts, much as a figure skater spins faster as she draws her arms to her sides.

Tornadoes have an additional energy source: the heat given off as water vapor condenses into liquid rain. The condensing water vapor produces the visible part of a tornado, called the condensation funnel, which is made up of water droplets. On Mars, there is too little water vapor in the atmosphere to contribute significantly to atmospheric convection on local scales. The cloud that we see in this image is produced by dust particles, not raindrops. The astounding heights of Martian dust devils are made possible because mass of an atmospheric column on Mars is less than 1 percent than that of a column on Earth. Transfer of heat from the surface into this less dense atmosphere can produce more vigorous convection, which will penetrate higher into the Martian atmosphere than its counterparts do on Earth.

Now, what would happen if you were caught in its path? Because the density of Mars' atmosphere is so low, even a high velocity dust devil is unlikely to knock you over. However, you might be blasted by any sand or dust particles carried along by the dust devil, which might scratch the visor of your space suit quickly if you were caught outside by this monster!

This vortex left behind a bright track as its winds disturbed the dust-covered surface, tracing the path of the dust devil from the northwest towards the southeast. A dust "skirt" twice as wide as the plume itself is seen near the base of the dust devil, but the bright track is the size of the plume and not the skirt. Dozens of smaller dust devils were also spotted in the same Context Camera scene, steadily vacuuming the surface and pumping dust up into the Martian atmosphere.

VIDEO
JPL has produced two excellent animations of this dust devil in action.
Clip 1
Clip 2

Written by: Paul Geissler   (4 April 2012)



 Image Products: All image links are drag & drop for HiView, or click to download
JPEG
Grayscale: map projected  non-map
IRB color: map projected  non-map
Merged IRB: map projected
Merged RGB: map projected
RGB color: non-map projected

JP2 DOWNLOAD
Grayscale: map-projected (876.0 MB)
IRB color: map-projected (691.0 MB)

JP2 EXTRAS
Grayscale: map-projected  (481.1 MB),
non-map  (335.2 MB)
IRB color: map projected  (396.5 MB)
non-map  (650.5 MB)
Merged IRB: map projected  (1011.1 MB)
Merged RGB: map-projected  (877.1 MB)
RGB color: non map-projected  (588.6 MB)

ADDITIONAL IMAGE INFORMATION
Grayscale label   Color label
Merged IRB label   Merged RGB label
EDR products

About color products (PDF)
HiView main page

 Observation Toolbox
Acquisition date:14 March 2012 Local Mars time: 3:02 PM
Latitude (centered):35.453° Longitude (East):201.545°
Range to target site:295.8 km (184.9 miles)Original image scale range:from 59.2 cm/pixel (with 2 x 2 binning) to 118.4 cm/pixel (with 4 x 4 binning)
Map projected scale:50 cm/pixel and North is upMap projection:Equirectangular
Emission angle:0.3° Phase angle:40.4°
Solar incidence angle:40°, with the Sun about 50° above the horizon Solar longitude:83.0°, Northern Spring
For non-map projected products:
North azimuth:97° Sub-solar azimuth:3.8°
For map-projected products
North azimuth:270°Sub solar azimuth:177.9°

Context map

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: Image: 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.