Microphysical Characteristics of Three Convective Systems with Intense Rainfall Observed By Polarimetric Radar and Disdrometer in Eastern China

Polarimetric radar and disdrometer observations obtained during the 2014 Observation, Prediction and Analysis of Severe Convection of China (OPACC) field campaign are used in this study to investigate the microphysical characteristics of three organized intense rainfall events (meiyu rainband, typhoon rainband and squall line) in eastern China. Drop size distributions (DSDs) during the passages of these convection systems are derived from measurements of a surface disdrometer, and the corresponding vertical characteristics of radar variables and inferred hydrometeor distributions are obtained from the Nanjing University C-band polarimetric radar (NJU-CPOL). Although the environmental moisture and instability conditions are different, all three events possess favorable environment for warm rain processes. Convection is tallest in the squall line where abundant ice-phase processes generate large amount of rimed particles (graupel and hail) above the freezing level and possess the largest surface raindrops among these three events. The lower storm tops in both the typhoon rainband and meiyu cases composed of less active ice processes above the freezing level but hold equally high medium to small raindrop concentration below causing high surface rainfall rates. The typhoon rainrate is more intense than that of meiyu, enhanced by higher coalescence efficiency. A revised N_w-D_m space diagram based on the disdrometer and NJU-CPOL analyses, is constructed to describe microphysical processes over these different cases and illustrate the relative importance of the ice-phased and warm-rain processes to the heavy rainfall.