Analysis of the Environmental Parameters of Warm-sector Heavy Rainfall in Different Types in Guangdong Province During Rainy Season in Recent 10 Years

WANG Rui; JIANG Yin; LI Chao; CHEN Xunlai; WANG Mingjie; WANG Deli

doi:10.16032/j.issn.1004-4965.2025.019

Abstract：Based on the rainfall data of Guangdong National basic meteorological Stations,regional automatic stations and NCEP FNL reanalysis data,73 typical warm-sector heavy rainfall cases in Guangdong during 2013-2022 were divided into four types according to circulation characteristics.They are shear line,low vortex,southerly wind,and backflow types.The characteristics of spatiotemporal distribution and physical quantities representing atmospheric static instability,energy,water vapor and dynamic conditions were analyzed statistically.The main results are as follows:(1)The southerly wind type has the highest frequency,and the backflow type has the lowest frequency.67％of the warm-sector heavy rainfalls occur during May-June,with 95％of the peak precipitation time occurring in the early morning and daytime.The southerly wind type shows the most distinct variation,with 72％of cases occurring from 05:00 to 08:00 in the morning and 12:00 to 17:00 in the afternoon.(2)The spatial distribution of warm-sector heavy rainfall shows significant differences among different types.The center of the backflow type warm-sector heavy rainfall is located on the western side of the Pearl River Estuary,which differs from the other three types with two main precipitation zones.(3)The key environmental parameters different types of warm-sector heavy rainfall indicate that none of the types require strong conditional instability,and the temperature difference threshold between 500 hPa and 850 hPa is only about 22 ℃.All of them need abundant water vapor,with the precipitable water threshold for the backflow type being the lowest(50 mm).Significant differences exist in energy and dynamic condition thresholds among 4 types.The backflow type requires weaker energy conditions and lower-tropospheric wind speeds,but stronger vertical wind shear from surface to 6 km.