基于超阈值取样的中国不同重现期降雨强度空间分异特征及强降雨变化模态(1961～2016年)

不同重现期下的降雨强度对于城市防洪减灾具有重要科学和现实意义。利用中国1961~2016年的535个日值降水站点数据，采用日降雨量的90%、95%和99%分位数阈值，对比分析不同超阈值取样下的中国不同重现期降雨强度空间分异特征和强降雨变化模态。结果表明：（1）3种分位数降雨阈值均呈东高-西低的空间分异特征。相比绝对阈值，日降雨量的95%和99%分位数阈值用于研究大雨和暴雨是相对合理的。（2）3种超阈值样本下的中国不同年遇型降雨强度受区域气候环境和地形条件影响，其空间演变特征具有相似性，均呈现出从东部沿海向西和向北扩张的趋势，但相同年遇型下的降雨强度空间格局在3种超阈值取样方法下差异较大。（3）EOF分析即经验正交函数分解表明在绝对阈值和相对阈值取样下的中国强降雨变化模态具有一致性，前三模态方差解释率可以达到54%以上，且第一、二和三模态的方差解释率均超过10%，分别达到约30%、14%和11%，均表征了中国年际强降雨量的不同变化规律特征，具有明显的气候物理意义。

Spatial Variability of Different Return Period of Rainfall Intensity and Variation Patterns of Heavy Rainfall in China from 1961 to 2016 Based on POT Sampling

Rainfall intensity under different return periods has important scientific and practical significance for urban flood control and disaster mitigation. In this research, using the data of 535 daily rainfall stations in China for 1961-2016 years, using the threshold value of 90%, 95% and 99% quantiles of daily rainfall amounts, the spatial differentiation characteristics of rainfall intensity and the change mode of strong rainfall in different return periods of different POT are compared and analyzed. The results showed that: Firstly, the three thresholds of rainfall amounts above were characterized by spatial differentiation from east to west. Compared with the absolute threshold, the 95% and 99% quantile thresholds of daily rainfall amounts are relatively reasonable for heavy rainfall and storm rainfall. Secondly, the different return period of rainfall intensity in China under three kinds of POT was influenced by regional climate and terrain conditions, and its spatial evolution features are similar, all of which showed a tendency to expand from the east coast regions to the west and north regions, but the spatial pattern of rainfall intensity under the same return period was very different under the three POT methods. Thirdly, EOF analysis showed that the variation modes of strong rainfall in China under absolute threshold and relative threshold are consistent, the variance interpretation rate of the first three modes can reach more than 54%, and the explanatory rates of the variance of the first, second and three mode are more than 10%, reaching about 30%, 14% and 11% respectively, which all represent the different variation features of annual strong rainfall in China. It has obvious climatic and physical significance.