Investigating the Microphysical Characteristics and Environmental Influences of Warm‐Rain Precipitation in Fuzhou Region of China

Abstract Microphysical characteristics of warm‐rain precipitation that occurred in Fuzhou region during warm seasons of 2022 and 2023 have been investigated by using polarimetric radar data. Results of a modified warm‐rain identification algorithm indicate positive Z DR variation in the liquid layer should be added as a criterion to prevent events dominated by breakup‐coalescence balance being mistakenly classified as warm‐rain events, causing the inaccuracy of quantitative precipitation estimation (QPE). Comparative analysis suggests that stratiform, convective and warm‐rain precipitation are distinguishable in Cao and Zhang parameter space due to the nature of clustering within concentrated ranges. Convection during certain life stage exhibits similar feature as warm‐rain precipitation in Kumjian and Ryzhkov (KR) parameter space, whereas initial Z DR and vertical variations of Z H and Z DR could be useful to separate these two precipitation types. Vertical profiles of polarimetric variables ( Z H , Z DR , K DP ) in warm‐rain precipitation all increase toward the ground, which is associated with lower echo‐top and storm‐top freezing levels than convective precipitation. Microphsysical processes above the melting layer significantly influence the precipitation growth processes below according to analysis of two typhoon‐related cases. Some insights are gained to the development of a warm‐rain identification algorithm, such as monotonically increase of Z H and Z DR in the liquid layer and suitable range of initial Z DR , in addition, synoptic environmental conditions, e.g., vertical velocity, lifting condensation level and moisture flux, could serve as auxiliary conditions to accurately identify warm‐rain processes, but further research is needed to determine how to utilize them specifically.