近34a青藏高原年气温变化

Change of Annual Air Temperature over Qinghai-Tibet Plateau during Recent 34 Years

对高原地区34 a(1971—2004年)82站共13 883 d的逐日日平均气温、日最高气温和日最低气温资料进行了统计,用REOF方法进行了分区,并讨论了趋势变化,结果表明:①无论年平均气温,还是年平均最高气温和最低气温,以35°N为界的南北变化的区域特征明显。在年平均气温和年最低气温中,西藏地区的累计方差比青海地区大,年最高气温中青海地区的累计方差比西藏地区大。②青藏高原地区年温度的分布主要取决于海拔高度、地理位置和地形的影响,而年温度的标准差与高原地区年降水的分布相似,但趋势相反,标准差大的区域主要在高原的西北部和四川的西南部。③高原大部分地区年平均气温、年最高和最低气温基本上是以增温的趋势为主,高原的西北部地区年平均气温增温幅度最明显,尤其以柴达木盆地增温幅度最大,增加幅度为0.8℃.(10a)-1以上。年最高温度青海的增幅比西藏明显,而年平均最低温度西藏的增幅比青海明显。

Some statistic work have been done to analyze the climate change in the area of Qinghai-Tibet Plateau using the daily meteorology series of 82 stations from 1971 to 2004 （with a series length of 13 883 days in total）, which include mean temperature, maximum temperature, minimum temperature. REOF method was used for regionalization and the trend for the different sub-regions have been analyzed and discussed. We can get the main conclusion listed below： （1） For both the northern and southern part divided by 35°N, the variation of annual mean temperature, annual mean maximum temperature and minimum temperature showed some obvious regional characters. The cumulative variance of the annual mean temperature and minimum temperature was greater in the region of Tibet than in the region of Qinghai, while that of annual maximum temperature was just the opposite. （2） The distribution of annual temperature in Qinghai-Tibet Plateau was mainly decided by the altitude, geographical location and terrain. The standard deviation had a similar distribution as the annual precipitation in the Plateau region but with an opposite trend, and the sub-regions with greater standard deviation mostly situate in the Northwest part of the Plateau and the Southwest part of the Sichuan Province. （3） For the most part of the Plateau, there was a common increasing trend in the annual mean temperature, maximum and minimum temperature, especially for the Qaidam Basin with the greatest magnitude （more than 0.8℃ per ten years） for such warming. However, the annual maximum increased fast in the Qinghai than in Tibet while the annual minimum temperature has a greater magnitude for increasing in the Tibet than in Qinghai.