典型干旱指数在滦河流域的适用性评价

Applicability of Typical Drought Indexes in the Luanhe River Basin

利用1957—2010年滦河流域9个代表气象站逐月降水量资料及滦河三道河子、韩家营、承德、下板城和滦县站的1956—2000年逐月天然径流量资料,分别应用降水距平百分率、标准化降水指数(SPI)、降水Z指数及径流距平百分率,评价滦河流域干旱情况,并比较4种干旱指数的评价效果。结果表明:降水距平百分率反映干旱程度较轻;与降水Z指数相比,SPI指数能较客观地反映滦河流域干旱程度,3种气象干旱指数在滦河流域的适用性评价结果,SPI指数优于降水Z指数和降水距平百分率;而径流距平百分率的水文干旱指数评价结果与实际旱情更为吻合。但是,这4种干旱指标缺乏综合性和机理性,尚需加强降水、气温、蒸发、径流量等因素的综合考虑,提出反映干旱内在机理的指标。

Based on the monthly precipitation data from 9 meteorological stations during the period of 1957-2010 and the monthly runoff volume data from 5 main hydrometric stations in the Luanhe River Basin during the period of 1956-2000,in this paper drought in the Luanhe River Basin was discussed,and the results were compared using the precipitation anomaly percentage,standardized precipitation index,precipitation Z-index and runoff volume anomaly percentage.The results showed that the drought degree explained with the precipitation anomaly percentage was slighter.Compared with the precipitation Z index,SPI could be used to objectively reflect the drought degree in the drainage basin,and it was more ideal in reflecting the drought degree than the precipitation Z-index and precipitation anomaly percentage based on the applicability evaluation results of three meteorological drought indexes.Evaluation results of runoff volume anomaly percentage were consistent with the actual situation and suitable for drought evaluation in the Luanhe River Basin.However,there was a lack of integrity and mechanism of these four drought indexes,and it was necessary to comprehensively consider the factors including precipitation,temperature,evaporation and runoff volume so as to put forward a drought index reflecting the inherent mechanism of drought in the drainage basin.