Locally-originated typhoons in the South China Sea (SCS) are characterized by long duration, complex track, and high probability of landfall, which tend to cause severe wind, rainstorm, and flood disasters in coastal regions. Therefore, it is of great significance to conduct research on typhoon precipitation microphysics in the SCS. Using GPM satellite observations, the precipitation microphysics of typhoons in the SCS are analyzed by combining case and statistical studies. The precipitation of Typhoon Ewiniar (2018) in the SCS is found to be highly asymmetric. In the eyewall, the updraft is strong, the coalescence process of particles is distinct, and the precipitation is mainly concentrated in large raindrops. In the outer rainbands, the “bright-band” of melting layer is distinct, the melting of ice particles and the evaporation of raindrops are distinct, and there exist a few large raindrops in the precipitation. Overall, the heavy precipitation of typhoons in the SCS is composed of higher concentration of smaller raindrops than that in the western Pacific (WP), leading to a more “oceanic deep convective” feature of typhoons in the SCS. While the heavy precipitation of typhoons in the SCS is both larger in drop size and number concentration than that in the North Indian Ocean (NIO), leading to more abundant rainwater of typhoons in the SCS. For the relatively weak precipitation (R < 10 mm h⁻¹), the liquid water path (LWP) of typhoons in the SCS is higher than that of the NIO, while the ice water path (IWP) of the locally-originated typhoons in the SCS is lower than that of the WP. For the heavy precipitation (R ≥ 10 mm h⁻¹), the LWP and IWP of typhoons in the SCS are significantly higher than those in the WP and NIO.

The microphysical characteristics of precipitation and their differences among four typical weather systems over Hainan Island were investigated via multi-source observations from 2019 to 2023. We find that the cold fronts (CFs) have the greatest concentration of small raindrops, with a more substantial raindrop condensation process. The subtropical highs (SHs), with primarily deep convection and more prominent evaporation at low levels, lead to greater medium-to-large raindrops (diameters > 1 mm). Tropical cyclones (TCs) are characterized mainly by raindrop condensation and breakup, resulting in high concentrations of small raindrops and low concentrations of large raindrops. The trough of low pressures (TLPs) produces the lowest concentration of small raindrops because of evaporation processes. The convective clusters of the SHs are between maritime-like and continental-like convective clusters, and those of the other three types of weather systems are closer to maritime-like convective clusters. The relationships between the shape parameter (μ) and the slope parameter (Λ), as well as between the reflectivity factors (Z) and the rain rates (R), were established for the four weather systems. These results could improve the accuracy of radar quantitative precipitation estimation and the microphysical parameterizations of numerical models for Hainan Island.