Gaoyuan qixiang (Feb 2024)
Analysis of Atmospheric Environment Characteristics and Radar Characteristics of Three Short-time Heavy Precipitation Cases under Different Influence Systems in Central Yunnan
Abstract
Based on conventional observation data， NCEP 1°×1° reanalysis data， hourly and 5min automatic station precipitation data， and CINRAD/CC Doppler radar data in Kunming， three short-time heavy precipitation cases under different influence systems during the main flood season of 2021 in central Yunnan are studied.The characteristics of precipitation， circulation pattern， atmospheric environment and structure， shape and evolution of radar echoes are compared and analyzed.The results show that the difference of the three short-time heavy precipitation cases is mainly due to the difference weather systems on 500 hPa.There are shear lines at 700 hPa， but the formation seasons are different.There are convergence lines or weak cold fronts on the ground.The environmental conditions of the three cases are consistent with those of other regions of China in terms of unstable stratification， water vapor near the ground and vertical wind shear， however， there are significant differences in the total precipitable water， CAPE， SWEAT index.The shape of convective echo includes dot echo， block echo， strip echo， flocculent echo and so on.Convective storm type can be divided into high-echo-centriod convective storm， low-echo-centriod convective storm and mixed-echo-centriod convective storm.Short-time heavy precipitation has a single stage of some convective storm type， also has several convective storm types appearing at the same time.CAPE and SWEAT index have a certain correlation with convective storm types.Strong echo profile is columnar structure or tower structure.35 dBz strong echo is grounded without overhang characteristics.Short-time heavy precipitation is mostly generated by long- time stagnant or slow-moving convective echo， some short-time heavy precipitation is also generated in the "train effect" of radar echoes.The duration of short-term heavy precipitation formed by monomer with short life cycle is mostly within 1h， but the duration of short-term heavy precipitation formed by monomer combination and repeated generation and extinction or "train effect" is usually 1~3 h.The instantaneous rain intensity produced by high-echo-centriod convective storm can reach more than 10 mm·（5min）-1， while the rainfall intensity produced by low-echo-centriod convective storm and mixed-echo-centriod convective storm can range from 3~10 mm·（5min）-1， and a few can reach more than 10 mm·（5min）-1.
Keywords
