中国降水及流域径流均匀度时空特征及影响因子研究

在气候变化与人类活动综合影响下,降水过程与地表径流关系一直是气象水文学研究的热点与难点。基于全国554个雨量站点日雨量数据及370个水文站点月径流数据,利用基尼（Gini）系数和相似性分析（ANOSIM）分析了中国降水和径流时空均匀度变化特征,研究表明：1）我国降水年内分配均匀度从西北到东南依次增加,径流年内分配均匀度东北较高,东南较低。降水年内分配均匀度在1980年前后没有发生明显变化,1980年后径流年内分配均匀度较1980年前在程度上更均匀,在范围上更广泛。2）我国东北、西北以及东南地区降水年内分配Gini系数呈下降趋势,其中长江流域和西南诸河上游呈显著下降趋势;径流年内分配Gini系数大部分地区呈下降趋势,其中长江流域、东南诸河呈显著下降趋势。1980年后,降水和径流年内分配Gini系数在长江流域和黄河流域的趋势正好相反,表明人类活动改变了径流天然的时间分配特征。3）在各水文区域内,降水和径流在量级、频率、历时以及时间上均具有空间相似性。1980年前后,降水空间分布均匀度在减小（不显著）,径流则相反（显著）。4）降水和径流特征变化在一定程度上具有一致性,但是在变化范围和程度上也有较大差异性。人类活动正在加深或反向影响降水引起的水文特征变化,使区域水资源的时空分布趋于均匀。

Spatiotemporal Patterns of Uniformity of Precipitation and Runoff over China and Related Influencing Factors

Investigation has been widely done addressing precipitation processes and runoff changes which is under the combined influences from human activities and climate changes. In this case, based on daily precipitation data from 554 rain stations and monthly runoff data from 370 hydrological stations, Gini coefficient and ANOSIM (Analysis of Similarity) methods are used to investigate the uniformity of precipitation and runoff in space and time. The results indicate that: 1) the uniformity of precipitation at annual scale is increasing from northwest to southeast China. The uniformity change of precipitation is moderate but the uniformity of runoff evidently increased after 1980. 2) The Gini coefficient of annual distribution of precipitation is observed to be decreasing in the northeast, northwest and southeast China, which is particularly significant in the upper southwest rivers and in the Yangtze River basin. The Gini coefficient of runoff variations is decreasing generally and it is particularly evident in the Yangtze River basin and in the basins of southeast rivers. After 1980, the Gini coefficient of precipitation and runoff are in adverse patterns in the Yangtze and the Yellow River basins, showing that human activities significantly altered the temporal distribution of runoff. 3) The precipitation and runoff in different regions have similarity in magnitude, frequency, duration and temporal distribution. The uniformity of precipitation in space is decreasing and that of runoff is increasing. Runoff changes should be consistent with precipitation changes. However, human activities such as construction of water reservoirs have greatly altered the runoff distribution which triggered the change of runoff uniformity in space and time. The study will be of great merits in terms of water resources management under influences of climate changes and human activities.