几种干旱评估指标在黄土高原的应用对比分析

Comparative Study on the Application of Several Drought Assessment Indices in the Loess Plateau

利用4种气象干旱指数计算方法,以农业气象干旱指标为参照,对2007年3月～6月陕西黄土高原43县区出现的干旱天气过程进行分析比较。结果表明,4种干旱指数计算结果比统计部门的实际旱情程度严重;相对湿润度指数计算出的干旱等级比实际统计等级严重;标准化降水指数计算结果反映出特旱面积过大;降水量距平百分率和气象干旱综合指数计算结果与实际情况基本一致。在干旱开始与结束日期计算中,相对湿润度指数计算结果与水利部所规定的水利行业标准计算结果一致;在干旱结束日期计算中,采用气象综合干旱指数和降水距平百分率指数计算的结束日期与水利部规定计算结果较为接近。

With the agricultural drought indices for reference,the drought weather processes appeared in 43 counties and districts of Shaanxi loess plateau from March to June,2007 were analyzed and compared by four methods.The results showed that the calculation results of the four methods showed more severe drought than that of the statistics departments;the drought level calculated by relative moisture index was higher than the actual level shown in statistics;the drought-affected area obtained by the standardized precipitation index was larger;the anomaly percentage of precipitation and comprehensive drought index were basically consistent with the actual situation.In the calculation of the start and end dates of drought,the calculation results of relative moisture index was the same as the calculation results of water conservancy industry standards set by the Ministry of Water Resources;in the calculation of drought end date,the calculated results using the integrated meteorological drought index and the precipitation anomaly percentage index were very close to that of water conservancy industry standard set by The Ministry of Water Resources.