中国区域1961~2010年降水集中指数（PCI）的变化及月分配特征  

Characteristics of Precipitation Concentration Index(PCI) Variations and Monthly Distribution of Annual Precipitation in China

作　　者：段亚雯 朱克云[3] 马柱国[1] 杨庆[1] 

机构地区：[1]中国科学院大气物理研究所东亚区域气候-环境重点实验室,北京100029 [2]中国科学院大学,北京100049 [3]成都信息工程学院大气科学学院/高原大气与环境四川省重点实验室,成都610225

出　　处：《大气科学》2014年第6期1124-1136,共13页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究发展规划项目"气候变化对我国东部季风区陆地水循环与水资源安全的影响及适应对策"2013BAC10B02;国家科技支撑计划"干旱;半干旱区域旱情监测与水资源调配技术开发与应用";公益性行业(气象)科研专项"中国区域土壤湿度预测系统研究及其对农业影响评估"GYHY201106028

摘　　要：降水的年内变化（月分配和季节变化）对农作物生长、水资源利用及管理具有重要意义,同时也是增暖背景下水循环发生变化的关键过程之一。降水集中指数（PCI,Precipitation Concentration Index）能较好的表征降水的年内集中程度,被广泛应用于相关研究。本文利用中国583个站点1961~2010年的逐月降水和气温观测资料,对中国及各典型区域的PCI进行了计算分析,研究了PCI的气候特征、变化趋势、降水月分配变化及PCI与气温季节较差的关系。结果表明,我国PCI的气候态呈现出由东南向西北逐渐递增的空间分布格局。湿润区PCI在11~17之间,年内降水较为均匀;半湿润区PCI为17~24;半干旱区PCI在24~27之间;而干旱区PCI则由27至47不等,降水集中程度较高。除华南地区外,1961~2010年间全国大部分地区PCI均呈现显著的下降趋势,并于1980年前后发生跃变,降水集中程度大幅降低,其中西北西部地区PCI下降速率最大,为-2.47（10 a-1）。华南地区PCI的变化则具有明显的阶段性特征,2003年以前呈弱的下降趋势,但2003年PCI发生突变,降水集中程度大幅增加。对典型区域的比较发现,干旱半干旱区和青藏高原降水集中程度的降低主要表现在夏季降水占全年总降水量比例的减小;而湿润区PCI和降水月分配的变化则存在明显的区域性差异,其中西南地区8~12月降水占全年降水的比例减少,而长江中下游及华南地区春秋季降水占全年降水的比例减小,冬夏季降水所占比例增大。Seasonal variability of precipitation is an important part of the hydrological cycle, and monthly distribution of annual precipitation strongly influences agriculture and water resources. The Precipitation Concentration Index （PCI） is an effective measure of the temporal inhomogeneity of annual precipitation and is widely used in many studies. Using rain-gauge data from 583 stations in China for the period 1961-2010, this paper documents the spatial characteristics of PCIs over the entire country and their long term variability. The relationship between PCI and seasonal temperature difference is also investigated. Our results show that in the arid northwestern China, PCIs are larger than 27; in the semiarid and sub-humid regions, PCIs are 24-27 and 17-24, respectively, whereas in the humid southeastern China the values are smaller than 17. Negative trends of PCIs are found in nearly the entire country during this 50-year period, expect for the southern part of China, where PCIs show a weak decreasing trend before 2003 but a reversal afterward. In approximately 1980, an abrupt change in PCI value occurred. Over the arid/semiarid regions and the Tibetan Plateau, PCIs decreased sharply due mainly to the reduction of the contribution of summer precipitation. Over the humid regions, large regional differences are apparent. In the middle-lower reaches of the Yangtze River and South China, the contribution of summer and winter precipitation increased, whereas the contribution of spring and autumn precipitation decreased.

关 键 词：中国 降水集中指数(PCI) 降水月分配 区域对比 

分 类 号：P467[天文地球—大气科学及气象学]