Statistical Analysis of Environmental Parameters of Warm-sector Rainstorms in the April-June Rainy Season of Heyuan
The sounding data and conventional surface observations of Heyuan for April-June from 2007 to 2022 were used to statistically analyze the spatial and temporal distribution characteristics and environmen-tal parameters of the warm-sector rainstorms of the city and key thresholds for forecasting different levels of warm-sector rainstorms were extracted based on the percentile method.The results are shown as follows.From April to June for the years studied,the warm-sector rainstorm events increased significantly month by month,and 72.5％of them appeared after the summer monsoon outbreak in the South China Sea.The spa-tial distribution of occurrence frequency gradually decreases from west to east,and the high frequency sta-tions are all located near the terrain of a northeast-southwest-aligned trumpet mouth.The average value of the difference between temperature and dew point at 925 hPa and 850 hPa,the temperature-dew point difference at 500 hPa,the integrated water vapor(IWV),uplift index,K index and 0-3 km vertical wind shear have clear indications for the occurrence of typical rainstorm events in Heyuan.
万方数据
维普
