Dunes: A Synthetic Aperture Radar (SAR) View 
Dan G. Blumberg and Ronald Greeley 
Department of Geology 
Arizona State University 
Tempe, Arizona 85287-1404 
e-mail address: Blumberg @ASUIP2.DNET.NASA.GOV 
Synthetic Aperture Radar (SAR) provides a unique perspective of Earth's surface and 
processes involved in its formation. Features formed by windblown sand and dust are abundant in 
deserts and are sensitive to climate and climate change. The JPL SAR (AIRSAR) was used to 
study surfaces in the Mojave. Results show that SAR provide information both on form and 
process as they pertain to windblown sand. High resolution SAR images can decipher dune types 
(i.e., star, linear, transverse dunes, etc.), and can provide an indication of surface roughness -- a 
key parameter in modeling aeolian activity. 
We show SAR signatures of dune types including: linear, transverse, and star dunes. The 
star dunes are easiest to identify in radar images due to a distinct blooming signature. Linear and 
transverse dunes can be identified due to their speckle return and dark interdunal surface. 
Interestingly, we noticed in radar images of the Stovepipe Wells dune field that even when the 
illumination is parallel to the crest of the dunes they are visible. 
Generally, calibrated SAR data can provide a useful tool in studying dryland environments. 
The anticipated launches of the Shuttle Radar Laboratory (SRL) will provide many scenes of wind 
swept regions on Earth. We anticipate that we will show some results from the SRL mission. 
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