东江流域近50年径流系数时空变化特征

Temporal and spatial characteristics of runoff coefficient variations in the Dongjiang Basin during 1964-2012

基于东江流域1964-2012年降雨、蒸发和径流等气象水文资料,采用线性倾向估计、M-K趋势检验及变化幅度和变化弹性等多种方法,结合ArcGIS自相关等空间统计分析技术,分析了东江流域径流系数的时空变化特征及其对降雨、蒸发和地表植被等影响因素的空间对应关系。结果表明:近50年来,东江流域年径流系数均呈上升趋势,且随着流域空间尺度的增大而增加,总体形成"南北低、中间高"的空间分布格局;径流系数变化幅度及变化弹性在20世纪90年代之后显著增加。径流系数变化幅度热度指数高值区大致位于东源及其以北地区。相较于蒸发和地表植被覆盖,流域降雨变化趋势与径流系数及其变动幅度热度指数的空间分布格局具有较好的一致性。本文可为识别变化环境下流域来水过程变异提供科学参考依据。

Based on meteorological and hydrological data such as precipitation,evaporation and runoff in the Dongjiang river basin from 1964 to 2012,using various methods including linear trend estimation,M-K trend test,amplitude of variation and elastic change and combining ArcGIS spatial statistical analysis technology such as autocorrelation,this paper analyzes the spatial and temporal variations of the runoff coefficient for this region and the space corresponding relation between the influencing factors such as rainfall,evaporation and vegetation and the runoff coefficient.The results show that all the annual runoff coefficients are on the rise on the Dongjiang river basin in recent 50 years.Annual average runoff coefficient increases with the increase of watershed spatial scale,which,on the whole,forms a spatial distribution pattern of high in the north and south,and low in the middle.The amplitude of variation and elastic change of the runoff coefficient significantly increased after the 1990s.The high heat index of amplitude of variation of runoff coefficient area is found in the north of Dongyuan county.Compared with evaporation and vegetation coverage,the changing trends of rainfall and runoff coefficients as well its heat index of amplitude of variation have good consistency on the spatial distribution.The research provides a reference basis for identifying variability of water inflow of river basins under a changing environment.