1961—2018年长江中下游地区暴雨过程的客观识别及其变化特征

利用区域性极端事件客观识别方法（OITREE）和长江中下游地区381站逐日降水资料对1961—2018年长江中下游地区的暴雨过程进行了客观识别。共识别挑选出245次区域性暴雨过程。长江中下游地区暴雨过程持续时间以2~3 d为主,最长为8 d,累积强度主要集中于（2~4）×10³ mm之间,累积面积主要集中于（2~5）×10⁵ km²之间。长江中下游地区暴雨过程主要发生在夏季,尤其是6—7月。湖北东南部、安徽南部和江西北部是长江中下游地区暴雨过程发生最频繁的地区。长江中下游地区暴雨过程既有长期变化趋势,又有年代际变化特征,近58年来发生频次显著增加（0.3次/(10 a)）,暴雨过程频次及5项指标均呈现出明显的年代际变化特征,20世纪60—80年代末期为暴雨过程偏少阶段,90年代呈增加趋势并在90年代末期达到峰值,在21世纪初急速下降后又有缓慢增加趋势。

Objective identification and variation characteristics of regional heavy rainfall events in the middle and lower reaches of the Yangtze River from 1961 to 2018

The regional heavy rainfall events (RHREs) are identified by using the Objective Identification Technique for Regional Extreme Events (OITREE) based on the daily precipitation data of 381 stations in the middle and lower reaches of the Yangtze River (MLYR) from 1961 to 2018. There are 245 RHREs in total in the MLYR. The duration of the RHREs in the MLYR is mainly 2 to 3 days, and the longest is 8 days. The cumulative intensity is mainly between (2-4) ×10 ³ mm, and the cumulative area is about (2-5) × 10 ⁵ km². The RHREs in the MLYR mainly occur in summer, especially from June to July. Southeast Hubei, southern Anhui and Northern Jiangxi are the areas where the RHREs occur most frequently in the MLYR. The RHREs in the MLYR has both long-term trends and interdecadal changes. The frequency of occurrence has increased significantly in the past 58 years (0.3 times per decade). The frequency of RHREs and the five indicators all show obvious characteristics of interdecadal variability. From the 1960s to the late 1980s, the RHREs were relatively rare. It showed an increasing trend in the 1990s and reached a peak at the end of the period, after a sharp decline at the beginning of 21st century, there was a slow increase trend.