1960-2011年西南地区干旱时空格局分析

基于西南地区130个气象站1960-2011年气象资料,计算了各站不同时间尺度的标准化降水指数(SPI),并采用Mann-Kendall趋势分析法和反距离加权插值等方法,分析了该区近52a以来干旱发生的时空变化特征。结果表明:(1)各区域干旱存在明显的年际变化波动且线性变化趋势较为显著,近12a来干旱次数明显增多。大部分区域干旱指数在春夏秋季均呈减少趋势,秋季最为明显,冬季反之。(2)空间分布方面,横断山地、广西丘陵、四川盆地东部和贵州高原南部春旱频率较高。夏旱主要发生在横断山地北部,若尔盖高原,四川盆地的西部和南部,云南高原中部和广西丘陵。云南高原南部,横断山地西南部,贵州高原和广西丘陵的秋旱频率较高。冬季干旱频率高值区主要集中在若尔盖高原、四川盆地西南部一带。

Temporal and Spatial Southwestern Distributions of Droughts in China in 1960-2011

Based on meteorological data of 130 meteorological stations in the southwest of China from 1960 to 2011,we have calculated standardized precipitation index(SPI) on different time scales,adopted the MannKendall trend analysis method and inverse distance weighted interpolation method,and analyzed the spatiotemporal variation characteristics of drought in the southwest in the past 52 years.The results indicate as follows:(1)In the aspect of annual variation,there was a notable inter-annual fluctuation in the southwest of arid region,and the linear trend was more obvious.Especially the drought frequency has significantly increased in the past 12 years.In most areas,the drought index showed a decreasing tendency,with the most obvious decrease in autumn,while that in winner was opposite.(2)In the spatial distribution of the south-west,the spring drought mainly distributed in Hengduan Mountains,Uuangxi Hilly,the east of Sichuan Basin and the southern part of Uuizhou Plateau.The summer drought was mainly located in the north of Hengduan Mountains,Zoige Plateau,the western and southern part of Sichuan Basin,the central part of Yunnan Plateau hilly,and Uuangxi Hilly.The areas with higher incidence of autumn drought were mainly located in the south of Yunnan Plateau,the southwest of Hengduan Mountains,Uuizhou Plateau and Uuangxi Hilly.The winter drought mainly concentrated on the Zoige Plateau and the southwest of Sichuan Basin.