1.中国科学院大气物理研究所;2.Institute of Atmospheric Physics,Chinese Academy of Sciences;3.China;4.Graduate University of Chinese Academy of Sciences
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（objective identification technique for regional extreme events, 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，较少事件强度超出320 mm/d，且区域性极端降水事件的影响范围呈显著上升趋势（~310 km2/yr）；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 yr），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积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；在华南地区区域性极端降水事件偏多年和偏少年，环流特征存在明显的差异。
Based on 176 meteorological hourly precipitation data over mainland of the South China (Guangdong and Guangxi) and monthly reanalysis data from ERA5 (European Centre for Medium-Range Weather Forecasts (ECMWF) fifth reanalysis) from 1981-2020, and applying the objective identification technique for regional extreme events (OITREE) and synthetic analysis, this study focused on the temporal and spatial characteristics of regional extreme precipitation event (REPE) over mainland of the South China, and further analyzed circulations in the years with high and low REPE frequency. The main conclusions are as follows. In frequency, the periodic variation of REPE frequency on the interannual scale is obvious, and it has obvious monthly distribution characteristics with the peak period from May to June. In extreme intensity and impacted area, the intensity of most REPEs in Guangdong and Guangxi is about 130 mm/d, and that of few events exceeds 320 mm/d, and the impacted area of REPEs shows a significant upward trend (~310 km2/yr). In comprehensive intensity, comprehensive index Z shows a significant upward trend (0.05/10 yr), which indicates intensity of REPE has a significant increasing trend. In the Greater Bay Area and northern Guangdong, the annual accumulated precipitation of REPEs and their contribution to annual total precipitation both show a significant upward trend, while in southern Guangxi, they show a downward trend. In addition, the circulations have obvious differences between the years with high and low REPE frequency.