西藏高原近40年的气温变化

利用西藏1961－2000年月平均气温、最高气温、最低气温资料，分析了近40年高原气温的变化趋势。结果发现，西藏大部分地区四季和年平均气温为升温趋势，尤其是秋、冬季；高原上普遍存在气温非对称变化现象，以Tmax、Tmin显著上升，但Tmin上升幅度大于Tmax为主要类型。Tmax上升主要表现在夏季，增暖以冬季最为明显，气温日较差降夏季外均显著减小。在各纬度带上均表现为升温，春、秋季升温最大，冬季次之。高海拔地区比低海拔地区升温强。近40年来西藏高原年平均气温以0.26℃/10a的增长率上升，明显高于全国和全球气温的增长率。20世纪60年代多异常偏冷年，90年代多异常偏暖年。

Change of Temperature in Tibetan Plateau From 1961 to 2000

Using the data of monthly mean temperature, maximum and minimum temperature from 1961 to 2000 in Tibet, the linear trends of the annual and seasonal temperature are analyzed. The results show that, the mean temperature displayed warming trend in most parts of Tibet, especially in autumn and winter. The asymmetry was detectable in Tibet, the type of asymmetry was mainly the increase of Tmax and Tmin, while Tmin increase was bigger than that of Tmax. The increase of Tmax occurred mainly in summer and Tmin,, in winter. The decrease of daily temperature range (DTR) was in all seasons (except summer). Warming was displayed at all latitudes, the increase was the strongest in spring and autumn, secondly in winter, the trend was stronger on the higher altitude than on the lower altitude. In addition, the linear trend of the warming for annual mean temperature over Tibet during the past forty years indicated an increase of 0.26 0C / 10 a, it is obviously higher than in other parts of China and in the whole globe. There were more anomalous cold years in the 1 960s, whereas anomalous warm years in the 1990s.