1979—2014年汾河流域干旱时空特征

Temporal and Spatial Characteristics of Drought from 1979 to 2014 in Fen River Basin

为全面分析近年来汾河流域的干旱特征,有效应对干旱风险,笔者采用汾河流域35个气象站1979—2014年的逐月降水数据,以标准化降水指数SPI为干旱评测指标,并采用Mann-Kendall检验等统计方法,获取流域在时间和空间尺度上的干旱分布特征。结果表明:36年来,流域年干旱强度和干旱范围呈减小趋势,四季的干旱强度减弱,夏、秋、冬季干旱范围减小;四季中冬季旱情最多且范围最广,夏季区域性干旱最多,秋冬春季发生连旱的可能性最高;多年平均下,干旱主要分布在流域北部,夏季南部干旱也分布较多,春、秋季局地干旱发生频率最高。SPI指数较好地反映了汾河流域近36年干旱的时空变化特征。

The paper aims to comprehensively analyze the drought characteristics of Fen River Basin in recent years and effectively response to drought risk.The authors obtained the drought distribution characteristics on the time and space scale of Fen River Basin by using monthly precipitation data of 35 meteorological stations in the basin from 1979 to 2014 with drought evaluation indicator as standardized precipitation index and statistical methods like Mann-Kendall and so on.The results showed that： in the past 36 years,the yearly drought intensity and drought range showed a decreasing trend,while the drought intensity of the four seasons and drought range of summer,autumn and winter all showed a decreasing trend; the drought was most and covered the largest area in winter,and the regional drought was most in summer; the probability of continuous drought was the highest in autumn,winter and spring; on a multi-year average,the drought mainly distributed in the northern region,and also distributed more in the south basin in summer,while local drought frequencies were the highest in spring and autumn.The SPI well reflected the temporal and spatial variation characteristics of drought in Fen River Basin in recent 36 years.