云贵高原北坡石漠化地区近50a降水波动分析——以四川省兴文县为例

FLUCTUATIONS OF PRECIPITATION IN THE ROCKY-DESERTED NORTHERN SLOPE OF THE YUNNAN-GUIZHOU PLATEAU IN RECENT 50 YEARS——AN EXAMPLE OF XINGWEN COUNTY,SICHUAN PROVINCE

全球气候变暖背景下的局地气候变化特征及其响应,是近年来的研究热点。兴文县是云贵高原北坡的典型石漠化区域,其多年降水变化在一定程度上可以反映该区的气候变化。对兴文县1959~2007年全年和分季节降水量进行Morlet连续小波变换,结果表明：全年与分季节降水总体上均呈减少之势,并具有多尺度波动的特征,不同季节的多年降水具有各自的变化规律。春季和夏季降水量丰贫交替的周期较长（超过9 a）,变化相对较缓;秋季、冬季和全年的降水丰贫更替周期较短（少于6 a）,变化相对较快。目前兴文县处于降水相对较丰时期的后半程,未来几年将进入降水相对偏少的时期。降水的波动减少趋势,将会加剧该区域水资源的供需矛盾,给农业生产带来不利影响,增加生态系统的脆弱性和影响喀斯特地貌的发育过程,并最终促进石漠化的发展。

Characteristics and responses of local climatic changes under the background of global warming had become a research focus.Xingwen County is a typical rocky desertification area of the Northern Slope of Yunnan-Guizhou Plateau;its precipitation variation can reflect the trends of the climate change of this area.Based on the Morlet continuous wavelet transformation of annual and seasonal precipitation during 1959～2007 in Xingwen,there is a decreasing trend in general,and multiscale fluctuation with diverse variances in different season.The variation period of precipitation in spring and summer is relatively longer with over 9 years,and that in autumn,winter and annual is shorter with less 6 years.At present,the Xingwen County is at the late stage of abundant precipitation,but will be less in the coming years.The decreasing trend will aggravate the imbalance between supply and demand of regional water resource,bring the adverse effect on agricultural production,increase the fragility of the ecosystem and influence the development of Karst,and promote the rocky desertification finally.