基于可变模糊算法的塔里木河流域干旱风险评价

Variable fuzzy algorithm- based risk evaluation of droughts over the Tarim River Basin

采用级差加权法确定了4种干旱指标的权重系数,分析了不同干旱指标对干旱的贡献,同时运用可变模糊法评价了塔河流域各县市的干旱等级并分析了塔河流域的干旱时空演变特征。研究结果表明:(1)级差加权法确定的干旱指标权重系数中综合减产成数的权重系数最大,秋季降水距平权重最小。巴州地区的农业生产受春旱影响最大,和田地区夏旱对农业生产影响最大,塔河流域西南部克州地区、阿克苏地区秋旱对农业生产影响大。(2)天山南坡地区各县市轻度干旱、中度干旱发生频率高,巴州地区特大干旱发生频率高,但阿克苏地区重度干旱和特大干旱发生频率低;昆仑山北坡县市干旱程度变化恰好与天山南坡各县市变化相反。

The weight coefficients of four kinds of drought index were determined by the use of the graded weighted technique and the contribution of the different drought indices to drought was analyzed. Also,based on the variable fuzzy method,the drought grade of each city and county in Tarim River Basin was assessed,and the spatiotemporal evolution characteristics of drought in the River Basin was analyzed. The results show that:( 1) among the drought index weight coefficients determined by the graded weighted technique, the weight coefficient of integrated reduction percentage is the maximum,while that of the autumn precipitation anomaly weight is the minimum.Agricultural production is mainly influenced by the spring drought in Bazhou Prefecture,the summer drought in Hotan Prefecture and the autumn drought in kezhou and Aksu Prefectures in the southwest part of Tarim River Basin;( 2) the frequency of the mild and moderate drought is high in cities and counties in the south slope of the Tianshan Mountain,however,the frequencies of the severe and extreme droughts are high in Aksu Prefecture. The drought situation in the north slope of the Kunlun Mountain is just opposite from that in south slope of TianshanMountain.