Quantitative analysis of the coupling mechanism between upperlevel troughs and typhoon residual moisture and construction of forecast identification methods:a case study of the heavy rainfall event in Changbai County in 2025
Yue Ning
Changbai County Meteorological Bureau of Baishan City,Baishan 134400
Abstract:Based on a heavy rainfall event in Changbai County in August 2025,this study utilizes automatic weather station data,reanalysis datasets,radiosonde observations,and radar products to diagnose the formation conditions of precipitation driven by the synergistic effects of an upperlevel trough and typhoon remnant moisture.The results indicate that the event occurred under the combined influence of the eastward and southward movement of the upperlevel trough and the northward transport of warm,moist air from typhoon remnants,with Changbai County situated in the overlapping region of pretrough ascent and lowlevel moisture convergence.Specifically,the sustained transport of warm and moist air by the 850 hPa lowlevel jet,the correspondence between 700 hPa convergence and upward motion,and the 500 hPa positive vorticity advection collectively provided favorable dynamic conditions for precipitation maintenance,while mountainous terrain significantly amplified moisture lifting and radar echo stagnation,serving as a crucial factor for the stationary rainband.Building upon this case diagnosis,the study proposes a coupled precipitation identification index and a hierarchical recognition framework based on key factors,including 850 hPa moisture flux,700 hPa moisture flux divergence,700 hPa vertical velocity,total precipitable water,and CAPE to provide operational forecasting references for similar weather processes.
岳宁. 高空槽与台风残余水汽耦合作用机制的定量分析与预报识别方法构建——以2025年长白县大雨过程为例[J]. 气象水文海洋仪器, 2026, 43(5): 90-93.
Yue Ning. Quantitative analysis of the coupling mechanism between upperlevel troughs and typhoon residual moisture and construction of forecast identification methods:a case study of the heavy rainfall event in Changbai County in 2025. Meteorological Hydrological and Marine Instrument, 2026, 43(5): 90-93.