The influence of precipitation on X-band polarimetric SAR: Results from TerraSAR-X and COSMO-SkyMed and terrestrial weather radars

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 model to demonstrating SAR observations in precipitation is necessary to accomplish this. Using 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 can be created. Model validation is presented using data from two cases: 1. X-SAR storm observations simulated from archived polarimetric S-band ground radar data incorporated with TerraSAR-X acquisitions over central Florida, U.S.A. and 2. dual-polarized C-band ground radar with simultaneous co-polar COSMO-SkyMed X-band SAR channels over northern Italy in June 2010. Given the challenges involved in characterizing the propagation effects, the results demonstrate the model capabilities well.