水电能源科学

利用1961～2020年南京市5个国家级气象观测站日降水资料、NCEP逐日再分析资料，对南京市暴雨覆盖范围及影响不同范围暴雨的大气环流进行分析。结果发现南京市暴雨主要集中于夏季，在空间分布上以小范围暴雨为主，相邻站点同时发生暴雨的概率明显大于非相邻站点，发生全市范围的暴雨次数相对较少。针对不同站点暴雨，通过聚类方法分析影响南京市暴雨的环流进行天气分型，结果表明引起南京市暴雨的天气型主要为季风型和气旋型，季风型占比较大，且随暴雨范围的增大占比增加；南京处在较弱的水汽辐合区时可能发生小范围暴雨，其中单站气旋型暴雨占比43%,而当较强的水汽辐合区覆盖南京大部分地区时，可能发生大范围暴雨，其中季风型暴雨占比80%以上，原因为季风影响下水汽从南方输送至南京周边有较强辐合，从而导致季风型暴雨占比较多、范围较大。

Based on the daily precipitation data of 5 national meteorological observation stations and NCEP daily reanalysis data from 1961 to 2020, the coverage area of rainstorms in Nanjing City and the associated atmospheric circulations were analyzed. The main conclusions are as following. The rainstorms in Nanjing City mainly occur in summer, and their spatial scale is usually small. The probability of simultaneous rainstorms in adjacent stations is obviously greater than that in non-adjacent stations. The rainstorms covering the whole city rarely occur. Based on the rainstorms covering different stations, the atmospheric circulation was analyzed by clustering method for synoptic patterns. The results show that the main synoptic patterns are the monsoon and cyclone types. The monsoon type accounts for a larger proportion, which increases with the rainstorm range. When the weak water vapor flux convergence covers Nanjing, the rainstorm range is small, particularly, small range rainstorms occurring at one station associated with cyclone type account for a relatively large proportion(43%). When the strong water vapor flux convergence area covers Nanjing, a large range rainstorm may occur. The monsoon type rainstorm may occupy more than 80%. The monsoon synoptic patterns in rainstorms are quite similar, with water vapor transporting from the south to Nanjing and convergent there.