학술논문
珠江三角洲"9·7"极端暴雨精细观测特征及成因 / Fine Observation Characteristics and Causes of"9·7"Extreme Heavy Rainstorm over Pearl River Delta,China
Document Type
Academic Journal
Author
陈训来; 徐婷; 王蕊; 李媛; 张舒婷; 王书欣; 王明洁; 陈元昭; Chen Xunlai; Xu Ting; Wang Rui; Li Yuan; Zhang Shuting; Wang Shuxin; Wang Mingjie; Chen Yuanzhao
Source
应用气象学报 / Journal of Applied Meteorological Science. 35(1):1-16
Subject
Language
Chinese
ISSN
1001-7313
Abstract
2023年9月7-8日珠江三角洲出现极端特大暴雨(简称"9·7"极端暴雨).应用多源资料分析该过程的精细化观测特征及成因,结果表明:"9·7"极端暴雨由高层辐散、中层弱引导气流、低层西南季风和台风海葵(2311)残涡共同造成,水平尺度约为100 km的带状中尺度对流复合体长时间维持,列车效应和暖云降水特征显著,雷达回波质心低,最强降水阶段不低于45 dBZ的强回波质心位于4 km高度以下,不低于30 dBZ的强回波在深圳持续时间长达21 h.该天气过程以中小雨滴为主且数浓度较大,当降水强度大于20 mm·h-1时,雨滴粒径增大但数浓度明显降低."9·7"极端暴雨持续时间、强度和落区与边界层低空急流脉动、急流核区位置对应很好,强降水出现在低空急流指数迅速加强后的1～2 h内,低空急流和低空急流指数变化对强降水具有重要指示意义.台风海葵(2311)残涡在珠江三角洲的长时间滞留是此次极端暴雨的天气尺度原因,深厚的边界层低空急流提供了良好的动力和水汽条件,对流风暴的持续生成和维持是此次极端暴雨的直接原因.
On 7-8 September 2023,the Pearl River Delta experiences an extremely heavy rainstorm,known as"9·7"extreme rainstorm.Multi-source data are comprehensively utilized,including high-density auto-matic weather station data,sounding data,wind profiler data,Doppler radar data,high-resolution meas-urements from FY-4B satellite,and the fifth-generation European Centre for Medium-Range Weather Forecasts(ECMWF)atmospheric reanalysis(ERA5),to analyze the fine precipitation characteristics and causes of this case.Results indicate that the extremely heavy rainstorm is characterized by area of cover-age,wide coverage area,long duration,and substantial rainfall.The extremely heavy rainstorm is caused by the combined interaction of 200 hPa upper-level divergence,the middle-level weak guiding flow,the lower-level southwest monsoon,and the residual vortex of Typhoon Haikui(2311).It is generated by the long-term horizontal scale of about 100 km banded mesoscale convective complex,with significant train effect and warm cloud precipitation characteristics.The centroid of intense echoes with an intensity greater than 45 dBZ is located below 4 km during the most intense precipitation stage,while intense echoes with an intensity greater than 30 dBZ can last for up to 21 hours in Shenzhen.In terms of raindrop distribution characteristics extreme rainfall is mainly caused by a high density of small and medium-sized raindrops.When the rainfall intensity exceeds 20 mm·h-1,the size of raindrop particles increases,but the numerical concentration significantly decreases.Results in an increase in raindrop size but a decrease in the number of concentrations.The duration,intensity,and area of extreme rainstorms have a strong correlation with the fluctuation of the low-level jet in the boundary layer and the location of the core area of the jet.Heavy rainfall occurs within 1-2 hours after a rapid strengthening of the low-level jet index.After the low-level jet index decreases,the intensity of heavy precipitation diminishes.Variations in the low-level jet and low-level jet index have significant implications for heavy rainfall.The prolonged presence of Typhoon Haikui residual vortex in the Pearl River Delta is the synoptic-scale cause of this extremely heavy rainstorm.The residence time of the lingering vortex exceeds 16 hours.During that time,the deep boundary layer low-level jet continuously transfers warm water vapor to the lingering vortex.Simultaneously,the water vapor from the western Pacific,carried by the northeast airflow of Typhoon Yunyeung,and the southwest mon-soon water vapor transfers through the Bay of Bengal,Indochina Peninsula,and the South China Sea,ulti-mately results in the formation of a stable mesoscale convergence line near the Pearl River Delta,causing an extremely heavy rainstorm.
On 7-8 September 2023,the Pearl River Delta experiences an extremely heavy rainstorm,known as"9·7"extreme rainstorm.Multi-source data are comprehensively utilized,including high-density auto-matic weather station data,sounding data,wind profiler data,Doppler radar data,high-resolution meas-urements from FY-4B satellite,and the fifth-generation European Centre for Medium-Range Weather Forecasts(ECMWF)atmospheric reanalysis(ERA5),to analyze the fine precipitation characteristics and causes of this case.Results indicate that the extremely heavy rainstorm is characterized by area of cover-age,wide coverage area,long duration,and substantial rainfall.The extremely heavy rainstorm is caused by the combined interaction of 200 hPa upper-level divergence,the middle-level weak guiding flow,the lower-level southwest monsoon,and the residual vortex of Typhoon Haikui(2311).It is generated by the long-term horizontal scale of about 100 km banded mesoscale convective complex,with significant train effect and warm cloud precipitation characteristics.The centroid of intense echoes with an intensity greater than 45 dBZ is located below 4 km during the most intense precipitation stage,while intense echoes with an intensity greater than 30 dBZ can last for up to 21 hours in Shenzhen.In terms of raindrop distribution characteristics extreme rainfall is mainly caused by a high density of small and medium-sized raindrops.When the rainfall intensity exceeds 20 mm·h-1,the size of raindrop particles increases,but the numerical concentration significantly decreases.Results in an increase in raindrop size but a decrease in the number of concentrations.The duration,intensity,and area of extreme rainstorms have a strong correlation with the fluctuation of the low-level jet in the boundary layer and the location of the core area of the jet.Heavy rainfall occurs within 1-2 hours after a rapid strengthening of the low-level jet index.After the low-level jet index decreases,the intensity of heavy precipitation diminishes.Variations in the low-level jet and low-level jet index have significant implications for heavy rainfall.The prolonged presence of Typhoon Haikui residual vortex in the Pearl River Delta is the synoptic-scale cause of this extremely heavy rainstorm.The residence time of the lingering vortex exceeds 16 hours.During that time,the deep boundary layer low-level jet continuously transfers warm water vapor to the lingering vortex.Simultaneously,the water vapor from the western Pacific,carried by the northeast airflow of Typhoon Yunyeung,and the southwest mon-soon water vapor transfers through the Bay of Bengal,Indochina Peninsula,and the South China Sea,ulti-mately results in the formation of a stable mesoscale convergence line near the Pearl River Delta,causing an extremely heavy rainstorm.