西南地区近40a气温变化的时空特征分析

利用西南地区96个测站近40 a的月平均、月平均最高、月平均最低气温资料,采用主成分分析、旋转主成分分析、小波分析、Mann-Kendall等方法对西南地区气温变化的时空特征进行了分析.结果表明:西南地区年平均、年平均最高、年平均最低气温的空间变化均具有很好的整体一致性,反映了年平均和年平均最高气温在1960s到1980s中期经历了一个由暖变冷的过程后,1980s后期开始呈现明显上升趋势,而年平均最低气温从1970s就开始呈单调上升趋势.青藏高原东侧山脉走向对气温变化的东西差异具有十分明显的影响.气温的主要空间异常可分为4个敏感区.小波分析表明,西南地区气温整体变化在近40 a主要存在准8 a的周期,其中四川盆地东部的气温在整个时段存在准20 a和准8～9 a的周期.

Spatial and temporal characteristics of temperature changes in southewst China during 1961-2000

On the basis of 40-year monthly average, maximum and minimum temperature data from 96 weather stations in Southwest China, the methods of principal component analysis, rotated principal component analysis, Mann-Kendall and wavelet analysis are used to analyze the spatial and temporal characteristics of temperature change. The main results show that the annual average, maximum and minimum air temperature in Southwest China have an obvious ascending tendency. In addititon, for annual mean, maximum temperature since latter 1980s warm to cold process took place in advance, but for annual minimum temperature the tendency is monotonic since 1970s. The large topography in east of the Tibetan Plateau has an obvious effect on the difference of temperature changes between eastern and western areas. The temperature abnormal area can be divided into four sub-regions. The wavelet analysis shows that there is an 8 years periodic oscillation in this 40 years for the temperature in the whole Southwest China, and there are two periodic oscillations of 20 years and 8-9 years for temperature in the Eastern Sichuan Basin.