Typhoon short-term heavy precipitation warning based on dual-polarization radar observations of precipitation particle vertical distribution

Mesoscale convective systems within typhoon spiral rainbands often lead to localized short-term heavy precipitation, and their accurate prediction remains a challenging issue in operational meteorology. This study utilized S-band dual-polarization radar to observe typhoon processes and systematically analyzed the differences in vertical distribution characteristics of precipitation particles between inner and outer spiral rainbands. Results showed that inner rainbands were characterized by deep convective development (11.8 ± 1.2 km), active ice-phase processes (graupel particle content of 55% ± 10% at 5 km altitude), and strong melting layer features (Zdr peak value of 3.8 ± 0.5 dB); while outer rainbands were dominated by shallower convection, weaker ice-phase processes, and warm rain processes. Based on the vertical distribution characteristics of particles, a multi-parameter warning index system was constructed, incorporating parameters such as graupel particle content and zero-degree layer bright band intensity. Independent sample verification showed that the Probability of Detection (POD) of this warning method reached 84.6%, an improvement of 19.2 percentage points compared to traditional methods, with warning lead time extended to 25-40 min. This study elucidated the microphysical formation mechanisms of typhoon short-term heavy precipitation, providing a scientific basis for enhancing typhoon precipitation forecasting and warning capabilities.