Active remote sensing of cloud microphysics

We discuss recent progress in analyses of retrieved cloud properties by active sensors. We have developed several types of algorithms that can be applied to data obtained by cloud profiling radar (CPR) and lidar to retrieve cloud macroscale and microphysical properties. The retrieved properties include cloud occurrence, cloud particle phase, orientation and microphysics. Combined use of CPR and lidar has been recognized to be a powerful tool for the retrieval of cloud microphysics. Single scattering property of ice particles is one of the key elements in the analyses. It has been necessary to develop appropriate scattering theories and inversion methods that can take into account the particle shape and its orientation for the analyses of CPR and lidar data. We have been analyzing the data obtained by the ground based, ship-borne and space-borne active sensors. Space-borne active sensors CloudSat and CALIPSO successfully started global observations of cloud and aerosols in June 2006. The theoretical basis of the analysis of these active sensors is given. Global analysis of cloud macro-scale and microphysical properties has been performed. After these space missions, JAXA and ESA are planning a new space mission, EarthCARE which will carry four sensors including 95 GHz Doppler radar and high spectral resolution lidar. It will be launched in 2015 and is expected to provide information of cloud microphysics as well as vertical air motion. The retrieval algorithms for EarthCARE have been developed by using the existing radar and lidar data including CloudSat and CALIPSO.