Physics
Scientific paper
Dec 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010agufm.p23a1615g&link_type=abstract
American Geophysical Union, Fall Meeting 2010, abstract #P23A-1615
Physics
[5464] Planetary Sciences: Solid Surface Planets / Remote Sensing, [5470] Planetary Sciences: Solid Surface Planets / Surface Materials And Properties, [5494] Planetary Sciences: Solid Surface Planets / Instruments And Techniques, [6969] Radio Science / Remote Sensing
Scientific paper
In 2005, the planet Mars was illuminated 56 times for 20 minutes each by an unmodulated 75-cm wavelength circularly polarized wave transmitted from the SRI International 46-m antenna in the Stanford foothills in California. The direct signal and a Martian surface echo, separated by differential Doppler frequency shifts, were received simultaneously at the Mars Odyssey orbiter. We analyze the echo data using a two-scale quasi-specular scattering model, which uses high-resolution Mars Orbiter Laser Altimeter topographic data at positions along the specular track of the echo to correct for the large-scale surface variation. We solve for local surface scattering functions using a regularized matrix inversion method and three common surface scattering models. Optimizing the matrix inversion regularization over the course of each experiment requires consideration of the changing properties of the surface echoes caused by different viewing geometries. Here we determine a set of regularization constants spaced one second apart for each acquisition, which result in physically plausible surface scattering functions over the full range of echo types. We validate the results by comparing the regularized matrix inversion solution to solution-fits to known models, with respect to surface roughness. Assuming a Gaussian scattering function, we find that average surface roughness increases with decreasing latitude in the northern hemisphere, but rarely exceeds 2 degrees of root-mean-square (rms) surface slope north of 55 degrees latitude. The average rms surface slope is 1 degree between 50 to 60 degrees north latitude, but half that between 60 to 75 degrees north latitude. The southern hemisphere (coverage between 12 to 82 degrees south latitude) presents a more complicated picture, but is on average rougher than the northern hemisphere, and the rms surface slope rarely exceeds 5 degrees. The results are important for evaluating landing safety for future Mars exploration spacecraft.
Gunnarsdottir Hrefna M.
Linscott Ivan R.
Zebker Howard A.
No associations
LandOfFree
Surface Roughness Estimates From Mars Odyssey Bistatic Radar Experiments does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Surface Roughness Estimates From Mars Odyssey Bistatic Radar Experiments, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Surface Roughness Estimates From Mars Odyssey Bistatic Radar Experiments will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1495887