基于干旱指数与主成分分析的干旱评价——以锡林河流域为例

利用锡林河流域逐月气象数据,分析了历年降水与气温的最值变化;计算了标准化降水指数(SPI)与综合气象干旱指数(CI)并用其对研究区干旱状况进行表征;利用主成分分析法对锡林河流域的干旱情况进行评价。结果表明:1981-2016年的最高气温变化呈微弱的升高趋势,最低气温的变化趋势基本持平。最大降水量的变化趋势是减小的,各月的最小降水量基本趋于0。CI指数表明,36 a中只出现过轻旱事件,且春季最多,其次为秋季,夏季发生的最少。SPI指数表明,36 a中出现了重涝、中涝、轻涝、重旱、中旱、轻旱事件,且事件的危害程度越高发生的概率相对越小,冬季发生的旱涝事件大多危害程度相对较高。主成分分析结果表明,研究区气象因素的第一主成分主要反映水分胁迫对干旱的影响,第二主成分主要反映日照对干旱的影响,第三主成分主要反映气温对干旱的影响;综合得分结果表明,各地的干旱情况排名为:扎鲁特>巴林左旗>翁牛特旗>多伦县>化德>西乌珠穆沁>锡林浩特>林西县>东乌珠穆沁>朱日和>阿巴嘎旗>二连浩特>苏尼特左旗。

Drought Assessment Based on Drought Index and Principal Component Analysis: A Cased Study in the Xilin River Basin

The monthly meteorological data of the Xilin River Basin were used to analyze the annual variation of precipitation and temperature in the study area.The standardized precipitation index(SPI)and integrated meteorological drought index(CI)were calculated and used to characterize the drought conditions in the study area.The principal component analysis was applied to evaluate the drought conditions in the Xilin River Basin.The results showed that the maximum temperature increased slightly in 36 years,and the minimum one did not change substantially.The change trend of the maximum precipitation was reduced,and the monthly minimum precipitation trended basically to zero.The CI index showed that only some light drought events occurred in 36 years,and they were the highest in spring,then in fall,and they were the lowest in summer.The SPI index showed that the drought levels and flood events were different in 36 years,and the higher the disaster degree was,the lower the occurrence probability would be.In winter,the disaster level of drought and flood events was relatively high.The results of principal component analysis showed that the first principal component of meteorological factors in the study area reflected mainly the impact of water stress on drought conditions,the second principal component reflected mainly the effect of sunshine on drought conditions,and the third principal component reflected mainly the effect of temperature on drought conditions.The results of comprehensive scores indicated that the drought in various places was in an order of Zarut>Bahrain Left Banner>Wengniute Banner>Duolun County>Huade>West Wuzhumuqin>Xilinhot>Linxi County>East Wuzhumuqin>Zhurihe>Abaga Banner>Erlianhaote>Sunit Left Banner.