关键词: 地形台阶, 时空变化, 线性趋势, Mann-Kendall突变检测, terrains, spatio-temporal variation, linear trend, Mann-Kendall non-parametric test

Abstract: Based on the annual and monthly mean temperature data at 135 weather stations in Southwest China from 1961 to 2005, and according to altitude, topographical and climatic features, Southwest China was divided into three terrains with different altitudes or four subregions, the spatial-temporal characteristics of temperatures for the four subregions were analyzed. The results show that the annual mean temperature exhibited a clear warming trend in most Southwest China, especially in the high altitude regions, such as Xizang Plateau, but cooling trends in northeast Sichuan and northern Yunnan. Seasonal warming rates for the four subregions were successively winter, fall, and summer or spring in a descending order, which is different from that of the national mean temperature rising rates; and warming trend in winter was clearly stronger than those in other seasons. Annual mean temperatures of each subregion showed a marked declining trend or no significant changes from the 1960s to the mid-1980s, but have shown a significant warming trend since 1997. The Mann-Kendall non-parametric test results of subregion annual mean temperatures show that the warming abrupt change occurred in the late 1990s; and the abrupt change time was earlier in high altitude subregion than those in lower altitude subregions.