Using the hourly rainfall data of a national meteorological station and regional automatic weather stations in Fogang,the Micaps sounding data and ERA 5 reanalysis at the resolution of 0.25°×0.25°from the ECMWF,two unusually heavy rains,taking place on June 7-9,2020 and May 10-13,2022 respectively in the annually first rainy season of the county,were analyzed respectively.The results are shown as follows.Both processes occurred under the background of upper-level divergence maintenance,eastward movement of a mid-level shortwave trough and southward advancement of a low vortex and a shear,which provided dynamic conditions for persistent precipitation.A southwest low-level jet stream brought a steady stream of water vapor and energy.The difference is that the 2020 rainstorm was an obvious warm-sec-tor process,while the 2022 rainstorm was a process of frontal precipitation.For the 2020 rainstorm,the wa-ter vapor in the lower troposphere and boundary layer came consistently from the South China Sea,and for the 2022 rainstorm,the water vapor originated from the convergence between a cooler northerly airflow and a warmer southwesterly airflow.Analysis of the two rainstorms reveals the diurnal variation of the low-level jet stream and the corresponding relationship between the jet and precipitation in the occurrence time and inten-sity.
关键词
天气学/特大暴雨/水汽条件/佛冈县
Key words
climatology/unusually heavy rain/water vapor conditions/Fogang
维普
万方数据