Assimilation system development for additional EarthCARE obs: Doppler velocity, cloud extinction, Rayleigh backscatter

This report details the developments to the assimilation system at ECMWF in preparation for the inclusion of EarthCARE observations other than cloud radar and lidar data, such as cloud extinction and Doppler velocity, directly into the Four-Dimensional Variational (4D-Var) system. The work is divided into three sections. Firstly, the scientific basis for the observation operators of cloud extinction, Rayleigh backscatter and radar Doppler velocity are outlined. Secondly, the extensive developments to the assimilation system are reported, including the definition of new variable names required for the conversion of the observations into BUFR and Observation Database (ODB) format are also described. Finally, the system is tested using pseudo-observations of EarthCARE cloud extinction, Rayleigh backscatter and radar Doppler velocity using retrievals and parameterizations of CloudSat and CALIPSO data.