基于标准化径流指数的水文干旱特征分析:以塔里木河为例

运用标准化径流指数(standardizedrunoffindex,SRI)和标准化降雨指数(standardizedprecipitationindex,SPI)对塔里木河源流区月径流量和月降水量进行了全面系统的分析,结合历史干旱资料和游程理论分析干旱指数适用性和干旱变化特征,结果表明:1)3个月尺度的SPI和SRI均能够较好地反映塔河流域干旱特征,阿克苏河流域和开都河流域山区气象站SPI3和SRI3的相关性高于其他域;2)和田河流域和叶尔羌河流域的干旱发生频率大于阿克苏河流域和开都河流域,但其干旱历时小于阿克苏河流域和开都河流域;3)1987年以后源流区的轻度干旱年均干旱次数少于1987年以前,主要是因为降雨、气温的增加和水利工程设施的修建.耕地面积迅速增加是1987年以后的极端干旱的干旱历时和干旱烈度大于1987年以前的主要原因. 

Analysis on hydrological drought characteristics based on standardized runoff index: a case study in the Tarim River Basin

Monthly runoff and precipitation in the headwaters of the Tarim River were analyzed from standardized runoff index and standardized precipitation index. Applicability of drought index and related changing properties of droughts were investigated using historical observations and run theories. SPI and SRI on a 3-month time scale reflect well the changing properties of droughts within the Tarim River Basin. Correlation between SPI3 and SRI3 is more significant in the Hotan and Yerqiang River Basins than in other river basins Occurrence frequency of droughts in Hotan and Yerqiang River Basins is larger than in Arkasu and Kaidu River Basins. However, the duration of droughts in Hotan and Yerqiang River Basins is shorter than in Arkasu and Kaidu River Basins. The number of light droughts in headwater regions of Tarim River Basin after1987 is smaller than that before 1987,due to increased temperature and precipitation and massive construction of hydraulic facilities after 1987. In addition, substantially increase of crop lands after 1987 is a major contribution factor behind lengthening drought duration and intensified droughts compared to before 1987. This study sheds new light on the understanding of drought changes in a warming climate in arid river basins in China and also in similar river basins in other regions of the globe.