中文摘要：

为比较不同干旱指标的适用性,利用漳河灌区1973-2009年气象站逐月降水、蒸发资料,计算月、季尺度标准化降水指数SPI和月尺度标准降水蒸散指数SPEI。采用三阈值法,识别干旱过程,统计干旱历时和干旱烈度,采用适线法确定二者边缘分布,并利用GH Copula函数构造其联合分布,计算各干旱事件的重现期。通过与实际干旱资料进行比较,评价了各指标在漳河灌区干旱分析中的适用性,并采用适用性最好的干旱指标评价灌区干旱特征。结果表明：①在漳河灌区干旱分析中,月尺度SPI的适用性最好,所识别的干旱场次准确度高,干旱特征值合理;②漳河灌区干旱总体季节性特征不突出。严重干旱4a一遇,且多发生在用水高峰期的夏秋季,易导致用水保证率降低,严重威胁粮食安全;③通过月尺度SPI识别出的干旱过程较实际形成的干旱过程历时长,干旱出现时间提前。

英文摘要：

In order to evaluate the applicability of different drought indexes, three drought indices i. e. monthly-scale, seasonal-scale standardized precipitation index （SPI） and monthly-scale standardized precipitation evapotranspiration index （SPED in Zhanghe Ir- rigation Region are calculated with monthly precipitation, evaporation from 1973 to 2009. Three thresholds method is used to identi- fy the drought process and estimate drought duration and drought severity as drought characteristic values. The frequency curve fit- ting method is adopted to calculate the frequency of each drought characteristic variable. Then the joint marginal distribution of drought characteristic values is constructed with GH Copula, meanwhile, the drought recurrence interval of Zhanghe Irrigation Re- gion is estimated. The applicability of each index is evaluated by comparing with the actual drought information in Zhanghe Irrigation Region. The results shows that： ①The monitoring effect of monthly-scale SPI get the best monitoring effect for the real drought; ②Seasonal characteristics of drought is not significant. Severe droughts occur once every four years,and usually occur in summer and autumn; ③Drought events, identified by monthly-scale SPI, last longer than the actual drought process, and usually appears earlier.