A Fully Polarimetric Characterization of the Impact of Precipitation on Short Wavelength Synthetic Aperture Radar

When synthetic aperture radars (SAR) operating above 5 GHz began acquiring data clearly showing attenuation and backscatter from storms in the images, the notion that SAR is truly an “all weather” technology was challenged. With the recent launch of several dual-polarization X-band SAR systems, the capability of characterizing this impact became reality; however, a complete model describing SAR observations during precipitation is required to do this. Using real storm observations by fully polarimetric ground radars and microphysical models of electromagnetic scattering from hydrometeors, a quantitative characterization of the impact of precipitation on high-frequency SAR is presented here. The methodology is described to simulate X-band SAR observations of real storms from ground-based weather radars with an example of a squall line observed by the CSU-CHILL weather radar added to a TerraSAR-X image acquired at a different time. By conditioning the simulation on real data, the variability of radar observations is greatly reduced and more realistic than simulating from pure theoretical parameters. Given the challenges involved in characterizing the propagation effects, the results demonstrate the model capabilities well, and the results will apply to higher frequency systems for the future.