Spaceborne W-band and ground C-band radar observations: comparison with numerical scattering simulations

Although different active and passive microwave satellite remote sensors have been successfully used for observations of clouds in the last years, the first spaceborne W band (94 GHz) Cloud Profiling Radar (CPR) onboard the CloudSat satellite, which was launched in 2006, provides valuable information about global cloud properties. This work aims at presenting results of an investigation of microphysical characteristics of clouds by combining observations from CPR and a ground C-band Radar (5.6 GHz). The analysis of the different return signals, recorded by the two radars, is useful for retrieving microphysical parameters of cloud systems. Two meteorological events occurred over Apulia region are investigated: one of them refers to a winter non-precipitating stratiform cloud, while the second one is related to a summer precipitating convective cloud. CloudSat and ground radar images have been geo-referenced using the same projection system, and almost simultaneously combined and displayed for analysis, according to a procedure described in details in a previous communication. In the top boundary and upper part of the system the W-band radar can observe with more accuracy, when compared to the C-band radar, while within a certain middle range of heights cloud profile by both instruments are well comparable. Two wavelength radar observations are compared with the output of numerical simulations of electromagnetic scattering, which allow fast computations of scattering properties of particles, by means of T-matrix implementation. The aim of this comparison is to find a suitable particle size distribution, which can reproduce the measured radar reflectivity for both frequencies. In this way, it is possible to obtain more information in order to better understand the microphysical properties of observed clouds.