中文摘要：

利用宁夏气象台站1961—2010年逐侯降水量序列资料，研究了表征降水量时间分配特征的降水集中度（PCD）和集中期（PCP）的空间分布与年际变化特征。结果表明：宁夏降水PCP与PCD空间分布特征明显，中北部PCP比南部山区偏早1候，PCD自北向南逐渐减小，北部1年中最大降水出现的时间变率较大，且出现极端降水的可能性比中南部大；1961—2010年全区PCD与PCP呈微弱的下降趋势，但近20aPCD明显增大，PCP显著推迟；PCD与PCP显著正相关，PCP出现得越晚，PCD集中度越高；各地的PCD与年降水量、汛期降水量以及年日最大降水量都有非常好的正相关性，正相关中心区位于北部的惠农、陶乐、中卫，中部的盐池、麻黄山和南部山区的大部，上述地区降水越集中，年降水量、汛期降水量以及年日最大降水量越大，导致洪涝灾害发生的可能性将越大；宁夏汛期降水多雨年各地降水更集中，且大降水中北部大部易出现得早，南部出现得晚；中高纬的北极涛动和低纬的南海季风对宁夏降水集中度有着显著的影响，北极涛动偏弱的年份，南海季风爆发偏早的年份，宁夏各地年降水比较集中。

英文摘要：

Actually, most studies on the characteristics of spatiotemporal distributions of precipitation and its change trend are based on the annual or monthly average data in China. But these questions can not be made prom- inent about the change of maximum or minimum precipitation in a specific period. And these study subjects on the regional flood or drought are very important. So in this paper, based on the data of pentad precipitation from 1961 to 2010 including the main stations in Ningxia, the characteristics of spatiotemporM distributions of precipitation - concentration degree and precipitation - concentration period are studied. Using standard deviation, trend, correla- tion, synthesis and other statistical analysis methods, spatiotemporal distributions of PCD, PCP and their change trends are studied. Meanwhile, the effect of Arctic Oscillation and South China Sea monsoon in precipitation - con- centration period are discussed. The study in this paper is expected to reveal the law of the precipitation change, to provide the basis on the Ningxia drought and flood forecasting. The result shows that the spatial distribution of PCP and PCD in Ningxia are obvious, PCP in central and northern areas of Ningxia is 1 pentad earlier than that in south mountain part of Ningxia. PCD was reduced from north to south. The temporal variability of yearly maximum pre- cipitation in the north of Ningxia is bigger, and extreme precipitation in the north of Ningxia appears more likely than in the center and south of Ningxia. PCD and PCP in Ningxia displayed a weak decreasing trend from 1961 to 2010. But PCD was increased significantly and PCP was delayed significantly in recent 20 years. There is a good positive relationship between the PCD and PCP. The later PCP appears, more concentrative PCD is. There are good positive relationships between PCD and annual precipitation, flood season precipitation, daily maximum pre- cipitation, and the center regions of positive relationships locate in Huinong, Taole, Zhongwei, Yanchi, Mahuangs-