干旱指数在四川省的适用性分析

干旱灾害频发严重制约着四川省的农业发展,为合理分析四川省干旱情况,干旱指数的选择尤为重要。本文基于四川省39个气象站点1960年-2013年的气象资料,分别计算1961年、1994年、2006年和2009年-2010年各站点相对湿润指数M、气象干旱综合指数CI、标准化降水指数SPI和标准化降水蒸散指数SPEI,利用Arcgis反距离插值法进行空间插值,并与中国气象灾害大典记录的四川省典型年干旱情况进行对比分析,进而评价四种干旱指数在四川省的适用性。结果表明:对于1961年夏旱,M指数和CI指数均表现出无旱或轻旱,SPI指数结果较实际情况偏小,SPEI指数监测出了干旱的重灾区,效果在四个干旱指标中最好;1994年夏伏旱,M指数监测结果偏小;CI指数出现了空报,对川东地区和川西高原的监测结果偏小,SPEI指数在达县、巴中一带结果偏小,而SPI指数在成都、绵阳一带的结果偏小。2006年伏旱,M指数监测结果偏小;CI指数比M指数效果稍好,但结果仍然偏小;SPI指数和SPEI指数监测出的干旱特征与实际一致;2009年-2010年的冬春连旱,SPEI指数效果最好,M指数次之,SPI指数效果最差。SPEI指数最能反映四川省典型干旱年干旱的空间分布特征。

Study about application analysis of drought index in Sichuan Province

The selection of drought indexes is very important to the reasonable analysis of drought situation in Sichuan Province.Based on the daily meteorological data from 1960 to 2013 of 39 meteorological stations of Sichuan Province,we calculated the Relative Humidity Index (M),Composite Index of Meteorological Drought (CI),Standardized Precipitation Index (SPI),and Standardized Precipitation-Evapotranspiration Index (SPEI) of each station in 1961,1994,2006,and 2009-2010.We used inverse distance interpolation of Arcgis to conduct spatial interpolation,and compared the situation with the records of typical Sichuan drought disasters in the Encyclopedia of Meteorological Disasters in China.Thus,we evaluated the applicability of the four drought indexes in Sichuan Province.Results showed that:for the summer drought in 1961,the M index and CI index both indicated no drought or slight drought;the results of SPI index were smaller than the actual situation;and SPEI index reported the severely afflicted areas,showing the best effect of the four indexes.For the summer drought in 1994,the monitoring results of M index were small;CI index made false prediction,and reported smaller results in the eastern Sichuan area and western Sichuan Plateau;SPEI index showed smaller results in Bazhong and Daxian;and SPI index showed smaller results in Chengdu and Mianyang.For the midsummer drought in 2006,the results of M index were small;the results of CI index were a little better than M index,but were still smaller than the actual situation;the monitoring results of SPI and SPEI were in accordance with the actual situation.For the winter to spring drought in 2009 and 2010,SPEI showed the best results,M index came second,and SPI index was the worst.In a word,SPEI was the best drought index reflecting the spatial distribution of droughts in Sichuan Province.