Analysis of precipitation in repeated acquisitions collected by the COSMO SkyMed constellation in polarimetric mode

Effects of rain in SAR images have been noted since early missions. For SARs at X-band such as the satellites of the Italian Space Agency constellation COSMO SkyMed or the DLR TerraSAR-X, SAR returns from surface are attenuated by precipitation that gives a specific signature in SAR images that depend on polarization. Attenuation, jointly with a reduced space resolution determined by the Doppler spectrum of precipitation returns, limits the capability of detecting surface features during storms. On the other hand, such precipitation signature could be used for atmospheric studies or precipitation measurements. Characteristics induced by precipitation on polarimetric COSMO SkyMed images collected have been detected and analyzed. The analysis methodology exploits also the availability of coincident measurements of precipitation from ground based radars, used to reconstruct the component of SAR return due to precipitation.