1960-2011年辽宁省大暴雨时空分布特征

利用1960-2011年辽宁省61个国家气象站地面20-20时降水及逐小时降水观测资料，统计分析辽宁大暴雨时空分布特征。结果表明：辽宁省年平均大暴雨日数为6.5 d，年平均影响范围为17.5站次，两个大暴雨多发区分别位于辽宁东南部和南至西南沿海地区。辽宁东南部大暴雨多发区由于受台风、江淮气旋、华北气旋和蒙古气旋等多种系统及地形影响，易出现区域性和局地性大暴雨，大暴雨发生次数较多，降水量变化较大；降水量和降雨强度极值均较大，大暴雨中心出现在凤城，降雨强度最大达212 mm/h^-1。南至西南沿海大暴雨多发区易受台风和华北气旋及地形影响，以区域性大暴雨为主，降水量和降雨强度极值也较大，但最大降水量和降雨强度极值均与大暴雨日数的中心不一致。区域性大暴雨的降水量极值对大暴雨降水量极值的贡献最大。大暴雨平均降雨强度的逐时变化呈单峰型分布，08时降雨强度达最强，20时降雨强度最弱。辽宁省大暴雨日集中出现在7月下旬至8月上旬，8月大暴雨日略多于7 月。最早和最晚区域性大暴雨均是受江淮气旋影响，并出现在辽宁省南部地区。大暴雨日数具有明显的周期变化，主要年代际变化周期为10 a。区域性和局地性大暴雨主要周期分别为36 a和10 a。预计未来6 a辽宁省仍处于大暴雨较多的阶段，并可能多以局地性大暴雨的形式出现。

Temporal and spatial characteristics of heavy rainstorm from 1960 to 2011 in Liaoning province

Based on daily and hourly precipitation data at 61 national weather stations in Liaoning province from 1960 to 2011, the spatial and temporal climate change characteristics of heavy rainstorm were analyzed statistically. The result shows that the number of average annual rainstorm is 6.5 days, and annual average stations where heavy rainstorms were observed are 17.5 stations. High-incidence areas of two rainstorms are located in the southeast of Liaoning and southwestern to southern seacoast of Liaoning province, respectively. Regional and local heavy rain easily occurs in the area of high-incidence rainstorm because of influence of typhoon, Jianghuai cyclone, North China cyclone, Mongolia cyclone etc. and local geographical conditions in the southeast of Liaoning province. As a result, the frequency of heavy rain is high and precipitation changes largely. Extreme of precipitation and intensity both are large, and the strongest rainfall is up to 212 mm/h^-1 and appears in Fengcheng. On the other hand, a regional heavy rain also easily occurs in the area of high-incidence rainstorm because of influence of typhoon, North China cyclone and topography, so extreme precipitation and intensity are also larger in the south to southwest of Liaoning province. However, the centers of maximum precipitation and extreme intensity are not consistent with that of the number of rainstorm day. Extreme of regional rainstorm is a major contribution to that of rainstorm. Hourly variation of precipitation intensity has a peak at 08:00 and a valley at 20:00. Heavy rainstorm day mainly appears from the last ten days of July to the first ten days of August, and it is higher in August than in July. The first and last regional heavy rains are influenced by Jianghuai cyclone and both occur in the south of Liaoning province. It is a significant cycle for the heavy rain day and its main inerdecadal cycle is 10 years, while main cycles of regional and local heavy rain are 36 years and 10 years respectively. Forecast suggests that the heavy rain still often occurs in the next 6 years in Liaoning province, especially the local heavy rain.