1981~2020年华南地区区域性极端降水事件研究  

Study on Regional Extreme Precipitation Events over South China during 1981-2020

作　　者：杨雯婷 孙建华[1,2] 傅慎明 赵黎京[4] YANG Wenting;SUN Jianhua;FU Shenming;ZHAO Lijing(Key Laboratory of Cloud-Precipitation Physics and Severe Storms,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;University of Chinese Academy of Sciences,Beijing 100049;International Center for Climate and Environment Sciences,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;HCIG New-energy Co.,Ltd,Shijiazhuang 050000)

机构地区：[1]中国科学院大气物理研究所云降水物理与强风暴实验室,北京100029 [2]中国科学院大学,北京100049 [3]中国科学院大气物理研究所国际气候与环境科学中心,北京100029 [4]河北建投新能源有限公司,石家庄050000

出　　处：《大气科学》2024年第3期906-922,共17页Chinese Journal of Atmospheric Sciences

基　　金：国家重点研发计划项目2019YFC1510400;国家自然科学基金项目42075002。

摘　　要：基于华南地区176个国家级自动气象站资料以及1981~2020年ECMWF ERA5再分析资料,采用区域性极端事件的客观识别方法(OITREE)、合成分析等方法,本文研究了华南地区区域性极端降水事件的时空分布特征,并分析了事件偏多年及偏少年的大尺度环流特征。主要结论如下:区域性极端降水事件的频次在年际尺度上的周期变化较为明显,并具有较明显的月变化特征,高发时段为5~6月;在极端强度及影响范围上,华南地区大部分区域性极端降水事件强度约130 mm d^(-1),较少事件强度超出320 mm d^(-1),且区域性极端降水事件的影响范围呈显著上升趋势(约310 km^(2)a^(-1));在事件的综合强度上,综合指数Z呈现显著的上升趋势[0.05(10 a)^(-1)],表明事件强度呈现显著增加的趋势;在大湾区及广东北部,区域性极端降水事件的累计降水及其对总降水的贡献呈显著上升趋势,而在广西南部地区,两者呈下降趋势;在事件偏多年,华南地区存在显著的西南风水汽输送及整层水汽通量强辐合的特征,而在事件偏少年,华南地区具有整层水汽通量辐合偏弱的特征;一般降水日,850 hPa上华南地区位于弱偏东南风区,区域性极端降水事件降水日,华南地区位于气旋性环流的东南部,受到明显的西南风风速大值带影响。Using 176 meteorological hourly precipitation data over the mainland of South China(Guangdong and Guangxi)and monthly reanalysis data from ERA5(European Centre for Medium-Range Weather Forecasts,fifth reanalysis)during 1981–2020 and applying OITREE(objective identification technique for regional extreme events)and synthetic analysis,this study investigated the temporal and spatial characteristics of regional extreme precipitation event(REPE)over the mainland of South China.In addition,this study analyzed circulations in years with high and low REPE frequencies.The following conclusions are drawn from these investigations.In terms of frequency,periodic variations in the REPE frequency on the interannual scale are obvious and have clear monthly distribution characteristics that peak in May–June.For extreme intensity and impacted area,the intensity of most REPEs in Guangdong and Guangxi is approximately 130 mm d-1,while that of few events is greater than 320 mm d-1,and the impacted area of REPEs shows a considerable upward trend(about 310 km^(2) a^(-1)).In terms of comprehensive intensity,the comprehensive index Z demonstrates a remarkable upward trend[0.05(10 a)^(-1)],indicating that the intensity of REPE has a notable increasing trend.The annual accumulated precipitation of REPEs in the Greater Bay Area and northern Guangdong and their contribution to annual total precipitation exhibit a considerable upward trend,while in southern Guangxi,both parameters show a downward trend.In years with high REPE frequency,substantial water vapor transportation and intensive convergence of whole-layer moisture flux are noted over South China,while in years with low REPE frequency,relatively weak convergence of the whole-layer moisture flux divergence is observed.On days of normal precipitation events,South China is primarily dominated by weak southeasterlies at 850 hPa,while on days of REPEs,South China is located in the southeast of the cyclonic circulation and is affected by strong southwesterlies.

关 键 词：华南 区域性极端降水 客观识别方法 大尺度环流 

分 类 号：P445[天文地球—大气科学及气象学]