Abstract:Based on a persistent severe convective event that occurred in March 2023 over the hilly terrain in the southeastern coastal regions of China, we comparatively analyze the surface spectral characteristics of precipitation particles associated with isolated convective storms and squall-line convective systems by using the S-band dual-polarization radar data and the observations of surface precipitation particle spectra. The results show that the isolated convective storms during the hailfall concentration area exhibit larger particle sizes, more complex spectral structures, more pronounced fluctuations in total particle number concentration, and greater dispersion in the velocity and size spectra. All these features indicate that the internal ice-phase processes are even more vigorous in this stage. In contrast, squall-line convection systems are characterized by high-density hailstones, a relatively high concentration of small raindrops, and simpler spectral structures. For the two convective types, the peaks in precipitation particle concentration both appear near the high-reflectivity precipitation region following the concentrated hailfall stage, accompanied by narrowing spectral width and reduction in large particles. Moreover, the precipitation process is further divided into four distinct stages, each showing markedly different spectral characteristics. These findings could enhance the understanding of the microphysical processes of isolated and squall-line hail clouds and provide scientific support for short-time nowcasting and hail suppression operations.