Characteristics of ice over stratiform rain: Global statistics from the Dual-frequency Precipitation Radar and the proposed retrieval scheme

The Dual-frequency Precipitation Radar (DPR) on NASA's core Global Precipitation Measurement satellite is the first space-borne instrument that offers an opportunity of a dual-wavelength radar retrieval of the size and the mass concentration of hydrometeors, i.e., two microphysical parameters that control the mass flux through the weather systems. Our focus is placed on DPR observations over the stratiform rain where the analysis revealed a sharp increase in mass flux from ice to rain phase in the official algorithm. This is inconsistent with the expectation that mass flux varies little across the bright band. The proposed algorithm imposes continuity of the precipitation rate across the bright band which additionally helps in deriving bulk ice density. It is based on Bayes' rule with riming parameterized by the “fill-in” model. The radar reflectivity are simulated using the scattering models corresponding to realistic snowflake shapes. The algorithm is validated using the co-located polarimetric radar data collected for the GPM ground validation program. In the future, this dataset will be used for multi-frequency radar studies that aim at constructing high quality training datasets for artificial intelligence algorithms that are necessary to analyse the huge volume of data that will be generated by upcoming space missions such as the one proposed by Tomorrow.io