Study on Cloud-Rain Evolution During Precipitation Based on Multi-Frequency and Dual-Polarization Microwave Observations

This study presents precipitation and related microphysical processes observed by a self-developed ground-based five-band dual-polarization microwave radiometer in conjunction with disdrometer and vertically pointing micro rain radars (MRRs) during convective and orographically induced precipitation. The ground-based microwave radiometer has ten channels measuring in horizontal and vertical polarization at 10.65, 18.7, 23.8, 36.5 and 89GHz, where dual 89GHz channels can provide additional information on cloud-ice and melting cloud, which are rarely used in ground-based instruments so far. Measured brightness temperatures and polarization differences (vertical-horizontal) are validated by 3-D radiative transfer simulations (VDISORT) considering the role played by cloud-ice and melting particles, other than traditional cloud-rain particles. Observing measurements confirm the importance of the 89GHz polarization difference for separating the cloud-ice from rain and cloud-water component and quantitatively interpreting cloud-ice-rain concentration and distribution profiles by deep learning combing additional measurements from MRR and disdrometer.