开封近50年暴雨、大暴雨时空分布特征分析

利用1961—2009年近50年来开封地区逐日降水资料,对开封暴雨、大暴雨进行时空分布特征分析,结果表明:其年代际变化均呈波浪型,波峰为20世纪70年代,波谷为80年代,90年代回升,21世纪初大暴雨呈减少趋势.开封地区的暴雨具有明显的季节性特征,夏季暴雨最多,尤其是7月中下旬最为集中;多局部暴雨,少区域性暴雨,连续暴雨也较少;暴雨南部多北部少,而大暴雨东部、东南部多,西部少;年暴雨站次数与年降水量呈很好的正相关;夜暴雨多于昼暴雨,并分析了暴雨的成因和产生特大暴雨的天气形势.

Temporal and Spatial Distribution Characteristic of Rainstorm and Heavy Rain in Kaifeng Nearly 50 Years

Using the daily precipitation data of Kaifeng area from 1961 to 2009,analyzes the temporal and spatial characteristic of the rainstorm and heavy rain in Kaifeng.The results show that the decadal variability of rainstorm and heavy rain are the waves.The wave crest is in 1970s,the wave trough is in 1980s,the wave rises in the 1990s and severe storm in the early 21th century tends to decrease.The rainstorm has the obvious seasonal characteristic,mostly in the summer,and it is particularly most centralized in mid-July.The partial rainstorm,the few regional rainstorm,the continual rainstorm are also few.The rainstorm assumes more in south,few in north.But the heavy rain assumes more in eastern and southeast area,few in the west area.The times of station where rainstorm occurred in the year has very good relation with the year precipitation assumption.The rainstorm assumes more in night than in day.The paper analyzes the origin and the air synoptic situation of the especially heavy rain.