甘肃省天水市近60年暴雨时空分布特征分析

Spatial Temporal Distribution Characteristics of Rainstorm in Tianshui of Gansu in Recent 60 Years

利用1951—2010年天水市7个测站逐日降水实测资料,分析了近60年来该地暴雨的时空分布特征。结果表明:天水地区暴雨时间分布特征是20世纪60年代初至80年代末为暴雨的高发期,7月和8月是暴雨发生频次较高的月份,分别占总次数的52.6%和29.8%;空间分布特征较为明显,东部多于西部,清水、张家川等关山地区暴雨发生频次高,暴雨发生的次数与地形地貌有密切关系;影响天水暴雨的主要天气系统为副高外围西南气流型和高原低涡切变型。

Based on the daily precipitation observation data at 7 stations of Tianshui during 1951 to 2010, the temporal and spatial distribution characteristics of heavy rain events in Tianshui were analyzed. The results indicated that： the frequency of heavy rain events was higher from the early 1960s to the late 1980s, and mainly concentration occurred in July and August, accounts for about 52.6% and 29.8% of the total respectively. In addition, the spatial distribution of heavy rain events in Tianshui could be summarized as follows characteristics, the occur frequency of heavy rain events was higher in eastern region of Tianshui than that in the western region, like Qingshui and Zhangjiachuan. The frequency of heavy rain events was closely related to topography. Synoptic systems such as Northwest China vortex and west pacific subtropical high deeply affected the formation and intensity of the heavy rain events in Tianshui.