International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences
全球变暖使得极端降水事件的强度和频率均呈上升趋势，位于亚洲季风区的中南半岛和华南（INCSC）地区更易受到极端降水影响而发生洪涝灾害。本文利用逐日降水资料对1951~2015年INCSC地区湿季（5~10月）的极端降水事件进行客观分类，并对每一类极端降水事件的环流特征及年际、年代际和长期趋势特征进行了分析。结果表明：（1）根据降水中心位置，INCSC地区的极端降水可客观分为华南类、中南半岛类、缅甸—云南类和华南南部—越南北部类，它们所联系的大尺度流型（Large-scale meteorological pattern，简称LMP）以中高纬波列和热带偶极子环流为主。其中，华南类的LMP在对流层高层为类似于东亚—太平洋（East Asia-Pacific，简称EAP）遥相关型的“+ ? +”经向型波列，但中心位置较典型EAP型偏西南，中东部的负异常环流为关键系统，低层为位于低纬度地区的“+ ?”经向型波列。中南半岛类LMP特征为热带偶极子异常环流，对流层低层较高层更为显著宽广。其余两类极端降水LMP在对流层高层受Rossby波列影响，低层主要为偏弱的热带偶极子环流特征。（2）INCSC地区极端降水的频次呈显著上升的趋势，主要来自于华南类和中南半岛类极端降水的贡献。经向型波列的LMP频发是造成华南类极端降水增多的原因。（3）中南半岛与华南地区极端降水的空间分布具有反对称特征，从中南半岛类的角度看，阿拉伯海经中南半岛至南海的低压环流稳定维持不利于在华南地区形成极端降水。
Global warming has increased the intensity and frequency of extreme precipitation events. Indochina Peninsula and South China (INCSC) is located in the monsoon region and thus is vulnerable to extreme precipitation with flood disaster. Using daily precipitation data, this paper objectively classified the extreme precipitation events in the INCSC region during the wet season (May to October) over 1951 to 2015. The circulation characteristics and interannual, interdecadal and long-term trend characteristics of each extreme precipitation cluster were analyzed. The results suggest that (1) According to the location of precipitation center, the extreme precipitation in the INCSC region can be objectively grouped into South China, Indochina Peninsula, Burma–Yunnan, and Southern South China–Northern Vietnam clusters. The associated large-scale meteorological patterns (LMP) are characterized by mid-high latitude wave trains and tropical dipole circulation. The LMP of the South China cluster features a "+ ? +" meridional wave train in the upper troposphere, which bears some resemblance with the East-Asia Pacific (EAP) teleconnection pattern. However, the centers of LMP lie southwestward to the EAP counterparts. The negative anomaly circulation in central East China is the key system. In the lower troposphere, LMP features a "+ ?" meridional wave train located at low latitudes. The LMP of the Indochina Peninsula cluster features a dipole anomaly circulation of enhanced monsoon trough and Mascarene high pressure in the upper to lower troposphere. The LMPs of the other two clusters of extreme precipitation have a combination of Rossby wave train in the upper troposphere and the moderate tropocial diople in the lower troposphere. (2) The occurrence of extreme precipitation days in the INCSC region exhibits a significant upward trend, which is contributed by the South China and Indochina Peninsula clusters. The occurrence frequence of meridional wave-train LMP increased the extreme precipitation days in the South China cluster. (3) The extreme precipitation of Indochina Peninsula and South China clusters are antisymmetric with each other. From the perspective of the Indochina Peninsula cluster, the maintenance of low pressure elongating from the Arabian Sea via Indochina Peninsula to South China Sea is unfavorable for the occurrence of extreme precipitation in South China.