1961-2007年四川夏季降水的时空变化特征

基于1961-2007年四川地区119测站逐日降水资料, 利用EOF、REOF分析、趋势分析、M-K突变检验以及Morlet小波分析等方法, 研究了四川地区夏季降水的变化趋势、空间分布特征以及时间变化规律. 结果表明: 近47 a来四川夏季降水呈减少趋势, 在1962、1982年和21世纪初发生突变, 存在22 a和6~8 a的周期.四川夏季降水可分为4个区域: 一区(盆地东部)和四区(川西高原)夏季降水量长期变化呈增多趋势, 二区(盆地中西部)长期变化呈减少趋势, 三区(川西南山)变化趋势较为稳定, 呈小幅度增多趋势. 4个区域的夏季降水周期各有特点, 最长存在的周期为23 a左右, 其次还有16 a、14 a、12 a、8 a、6 a的周期变化.

Spatial-Temporal Variation Characteristics of Summer Precipitation in Sichuan, 1961-2007

Based on the precipitation data of 119 stations from 1961 to 2010, the temporal and spatial variations of summer precipitation in Sichuan were analyzed by using the EOF, REOF linear trend, Mann-Kendall analysis and Morlet wavelet analysis. The analyzed results are as follows: The summer precipitation presents a downward tendency during the 47 years. Abrupt changes appeared in 1962, 1982 and 2000, respectively. There were changing periods of 22 and 6-8 years. Spatially, the summer precipitation in Sichuan can be subdivided into the following four regions: east Sichuan basin, mid-west Sichuan basin, southwest Sichuan mountain region and western Sichuan plateau. Summer precipitation was increasing in east Sichuan basin and western Sichuan plateau, was decreasing in mid-west Sichuan basin and more stationary, perhaps with a little increasing, in southwest Sichuan mountain region. In the four regions, there were unique annual and decadal variations in summer precipitation, with changing periods of 23, 16, 14, 12, 8 and 6 years.