华南暖区暴雨事件的筛选与分类研究

利用逐小时降水资料,采用客观方法对1982~2015年华南地区暖区暴雨进行了筛选和分类研究。主要结果如下:华南区域暖区暴雨事件共计177例,暖区暴雨占筛选的暴雨事件的16.86%,表明暖区暴雨是华南非常重要的降水过程。暖区暴雨主要出现在4~7月,6月份最多,平均持续11.58 h。暖区暴雨事件发生位置主要集中在广东、广西的沿海地区和粤北山区,有四个降雨中心。产生华南暖区暴雨的天气形势主要有四类,切变线型、低涡型、南风型和回流型,不同类型的暖区暴雨对华南地区的内陆和沿海的作用不同,且南风影响下的暖区暴雨发生频率较高,影响较大,是一类较为重要的暖区暴雨。     

Classification of persistent heavy rainfall events over South China and associated moisture source analysis

Persistent heavy rainfall events (PHREs) over South China during 1981–2014 were selected and classified by an objective method, based on the daily precipitation data at 752 stations in China. The circulation characteristics, as well as the dry-cold air and moisture sources of each type of PHREs were examined. The main results are as follows. A total of 32 non-typhoon influenced PHREs in South China were identified over the study period. By correlation analysis, the PHREs are divided into three types: SC-A type, with its main rainbelt located in the coastal areas and the northeast of Guangdong Province; SC-B type, with its main rainbelt between Guangdong Province and Guangxi Region; and SC-C type, with its main rainbelt located in the north of Guangxi Region. For the SC-A events, dry-cold air flew to South China under the steering effect of troughs in the middle troposphere which originated from the Ural Mountains and West Siberia Plain; whereas, the SC-C events were not influenced by the cold air from high latitudes. There were three water vapor pathways from low-latitude areas for both the SC-A and SC-C PHREs. The tropical Indian Ocean was the main water vapor source for these two PHRE types, while the South China Sea also contributed to the SC-C PHREs. In addition, the SC-A events were also influenced by moist and cold air originating from the Yellow Sea. Generally, the SC-C PHREs belonged to a warm-sector rainfall type, whose precipitation areas were dominated by southwesterly wind, and the convergence in wind speed was the main reason for precipitation.     

不同类型华南暖区暴雨过程的环流特征

在对34年华南暖区暴雨的筛选和客观分类研究的基础上,继续深入研究不同类型暖区暴雨的环流特征与对流发生环境变量特征的异同.主要结果如下:大部分切变线型、低涡型和回流型暖区暴雨个例的环境场斜压性较强,其中回流型暖区暴雨在关键区斜压性最强,而南风型暖区暴雨个例的环境场斜压性相对较弱;所有类型暖区暴雨发生时对流层中高层的中纬度...