近30年我国南方区域持续性暴雨过程的分类研究

利用中国站点日降水资料对1981~2011年我国南方地区区域持续性暴雨(PHREs)进行了分类研究。按照区域内至少连续5 d或5 d以上有不小于10个格点分辨率0.25o(纬度)×0.25o(经度)]出现大于等于50 mm降水且相邻两日雨带重合率不小于20%的标准,采用客观分析的方法分别挑选出我国江淮区域和华南区域PHREs。江淮区域非台风影响的PHREs 31例,集中发生在6月中旬到7月中旬,平均持续8.29 d,华南非台风影响的PHREs 34例,集中发生在6~7月,平均持续6.24 d,这两类事件的发生频次和强度均呈年代际增长。江淮区域受台风影响的PHREs 4例,集中发生在7月中下旬到8月初。华南受台风系统影响的PHREs 31例,集中发生在7~9月,此类事件的发生频次和系统强度在2000年以后均明显上升。采用场相关的客观分类方法对非台风影响的PHREs进行较为细致的分类,将江淮区域持续性暴雨事件分为A型(主雨带在长江以南)、B型(主雨带在长江以北)和C型(主雨带在长江沿江地区),将华南区域持续性暴雨事件分为E型(主雨带在云贵高原以东)和F型(主雨带位于云贵高原和广西),该分类将为下一步的机制研究提供帮助。

Classification of Persistent Heavy Rainfall Events over Southern China during Recent 30 Years

The persistent heavy rainfall events (PHREs) over southern China during 1981-2011 are classified by utilizing the daily precipitation data at 752 stations in China. PHREs in the Yangtze and Huaihe River Valley (YHRV) and PHREs in South China (SC) during 1981-2011 are selected on the basis of the following criteria: More than 10 grids 0.25°(latitude)×0.25°(longitude)] in the area with daily precipitation of more than 50 mm lasting more than five days and rainband coincidence degree greater than 20%. The statistics reveal that 31 PHREs in the YHRV were concentrated between mid-June to mid-July with an average duration of 8.29 days, whereas 34 non-typhoon PHREs in SC were concentrated in June and July with an average duration of 6.24 days. Moreover, the frequency and intensity of these two types changed in decadal growth. PHREs affected by the typhoon systems in the YHRV were concentrated between mid-July and early August. Those occurring in SC were concentrated from July to September, and their frequency and intensity have increased since 2000. Objective pattern correlation statistics are used to classify and discuss the non-typhoon PHREs in detail. PHREs in the YHRV are divided into three types: (A) main rainbelt to the south of the Yangtze River (YR), (B) main rainbelt to the north of the YR, (C) main rainbelt along the YR, and PHREs in SC are classified into two types: (E) main rain belt to the east of the Yunnan-Guizhou Plateau and (F) main rainbelt located over the Yunnan-Guizhou Plateau and Guangxi Province. On the basis of such classification, the mechanisms of PHREs will be discussed in future studies.