北京地区夏季短时强降水时空分布特征

利用北京地区2006—2010 年187 个观测站的逐5 min 观测资料，对北京地区夏季短时强降水过程进行了统计分析。结果表明：空间上，北京地区的短时强降水主要分布在山前及山前的平原地区。靠近城区的西山山前以及城区是一个短时强降水的高发区(高发区A)，怀柔、昌平和顺义交界的山前地区到密云水库一带是另一个短时强降水的高发区(高发区B)。此外，位于平谷境内的山前地区也是一个短时强降水的易发区(高发区C)。时间上，短时强降水过程主要发生在午后到前半夜，维持时间主要集中在20～35 min，过程总降水量集中在20～30 mm。三个高发区比较而言，高发区B 由于兼具地形和水源两大有利因素，一方面更容易出现持续时间更短（约20 min 左右）的短时强降水过程，另一方面又有利于长持续短时强降水（约50 min）的形成。总体上，该高发区内的短时强降水过程也具有更大的过程累积雨量。

Temporal and spatial distribution of short-time heavy rain of Beijing in summer

By using rainfall dataset from 187 observation stations in Beijing during the period of 2006 to 2010, the short-time heavy rain (STHR) in summer is analyzed. The results show that STHR occurs mainly in the afternoon to mid-night with a rainstorm sustain time (Tsus) of mostly 20-35 minutes. The total precipitation (Rtot) is mostly 20-30 mm. Spatially, the piedmont region and the plains (region A) are the main locations of STHR. The front of Xishan, which is also near urban district, and urban district are regions with high incidences of STHR. The band from the piedmont in border region of Huairou County, Changping County, Shunyi County to Miyun Reservoir (region B) is another region with high incidences of STHR. In addition, the piedmont region in Pinggu County (region C) is also prone to STHR events. By comparing among the three high-incidence regions, region B, where has both favorable factors, i.e., the terrain and the water source, is more likely to presents shorter duration STHR (approximately 20 minutes) on one hand, and also is favorable to form long-maintained STHR (approximately 50 minutes) on the other hand. As a whole, the region B has a greater rainfall accumulation than the other two regions.