Precipitation rate estimation analysis for GPM-DPR pre-launch algorithm

The dual-frequency precipitation radar (DPR) on board the GPM (Global Precipitation Measurement) core satellite is equipped with two independent frequency channels, Ku- (13.6 GHz) and Ka- (35.5 GHz) band. This enables better retrieval of the DSD parameter and better accuracies in rainfall rate estimation than TRMM (Tropical Rainfall Measuring Mission) precipitation radar (PR). Le and Chandrasekar (2013) [1] developed a hybrid method to retrieve DSDs for GPM-DPR using airborne radar data. In this paper, precipitation rate is calculated using DSDs retrieved through the hybrid method based on assumptions of particle falling velocity. We also investigate potential relations between precipitation rate and dual-frequency parameters through direct parameterization. This analysis first goes through simulation procedure, and then applied to airborne data with attenuation corrected using method in [1]. Reasonable comparison of precipitation rate can be seen in between true precipitation rate, evaluation through DSDs and from direct parameterization.