Preliminary analysis of Shuttle Radar Laboratory (SRL-1) data to study aeolian features and processes

In April 1994, the Shuttle Radar Laboratory (SRL-1) obtained quad-polarization data in L-band (/spl lambda/=24 cm) and C-band (/spl lambda/=5.6 cm) and VV-polarized data in X-band (/spl lambda/=3 cm). Preliminary analyses show that radar backscatter coefficients (/spl sigma//sup 0/) can be used to map the aerodynamic roughness parameter, z/sub 0/, over large areas from orbit, as demonstrated by comparisons with measurements of z/sub 0/ obtained in the field. Although all wavelengths and polarizations show fairly good correlations with z/sub 0/ (r=0.78), L-band HV shows the best relationship (r=0.81). This result has potential use in regional studies of sand and dust transport, modeling atmospheric circulation, and general climate studies. SRL images of aeolian landforms were also studied, including dunes, sand sheets, and wind streaks. Dunes in the Stovepipe Wells area of Death Valley were clearly visible on L-band HV images, but not detected on C-band images. In the same area, L-band penetrated a sand sheet to reveal a buried fault scarp. L-band images in Namibia showed the classic linear dunes near Gobabeb and also revealed previously undetected sets of "cross dunes". Wind streaks were imaged in several areas, including Namibia where streaks are associated with the impact crater, Roter Kamm. These features enable mapping of near surface wind patterns.>