川滇地区气候特征与旱涝灾害变化趋势分析

Climatic Characteristics and Trend of Droughts and Floods in Sichuan-Yunnan Region

以川滇地区70个气象观测站点1961—2011年的降水、气温资料为基础，采用线性回归、M—K突变检验、反距离加权空间插值、小波变换等方法，分析了川滇地区近51a来气候变化特征和旱涝灾害趋势。结果表明：（1）近51a来川滇地区气温总体上呈增加趋势，气温倾向率为0．21℃／10a，增温趋势系数高达0．71，气温存在极其显著的长期增温趋势。川西高原年平均气温最低，云南省南部地区气温最高，海拔高度是影响该区气温空间差异的重要因素。（2）近51a来川滇地区降水量总体上呈减少趋势，平均递减率为10．76mm／10a。受西南季风与海拔高度的影响，降水量在空间分布上差异极大，川西高原与四川盆地西南周边地区降水量相对较少，四川盆地降水相对丰富，滇西南地区降水量最为充沛。（3）川滇地区气候暖干化趋势明显，分别在1997和1999年发生了增温和降水量减少的突变，旱涝灾害存在10～15a和28a的周期振荡，该区涝灾向旱灾转化的趋势明显。

By using methods of linear regression, the Mann--Kendall test, inverse distance weighted spatial interpolation and wavelet transform, the characteristics of climate and the trend of droughts and floods were analyzed based on temperature and rainfall data collected from 70 meteorological sites in Sichuan--Yunnan region from 1961 to 2011. Results showed as follows： （1） Temperature presented an increasing change over the last 51 years in Sichuan--Yunnan region with the tendency rate of 0.21 ℃/10 a, and has a significant long-term warming trend with the warming trend coefficient as high as 0.71. The annual averaged tempera- ture was affected most by the altitude with the lowest annual average temperature happened in Western Si- chuan plateau and the highest in the Southern Yunnan Province. （2） In the past 51 years the annual precipi- tation showed an decreased trend in Sichuan--Yunnan region with the decreasing rate of 10. 76 ram/10 a. The precipitation was influenced by the southwest monsoon and the altitude with the relatively low precipita- tion happened in West Sichuan Plateau and the surrounding area of the Southwestern Sichuan basin, relative ly abundant in Sichuan Basin and the most abundant in Southwestern Yunnan Province. （3） Climate warming and drying trend was obvious in Sichuan--Yunnan region with a sudden warming change and rainfall reduc- tion occurred in 1997 and 1999 respectively and droughts and floods oscillation periods of 10-15 years and 28 years. The trends of disasters changed clearly from floods to droughts in Sichuan--Yunnan region.