1961～2005年来青藏高原主要气候因子的基本特征

Basic characteristics of major climatic factors on Qinghai-Tibet Plateau in recent 45 years

基于69个气象台站的气象数据,对青藏高原地区1961～2005年来的主要气候因子特征进行了分析。结果表明:1961～2005年的45年间,青藏高原地区年平均温度呈上升趋势,其倾向率为0.265℃/10a,其中青藏高原地区冬季气温变暖趋势明显,春季变暖趋势不明显;20世纪80年代以来青藏高原地区的温度升高有加速的趋势。近45年来青藏高原地区年降水量呈现微弱增加趋势,其倾向率为8.21 mm/10a。青藏高原地区春季和冬季降水量都以增加趋势为主,但春季增加趋势远远大于冬季。青藏高原地区降水存在一定的周期性,32个站表现出短周期特性,为2～4年左右;11个站表现出中周期特性,为5～8年;6个站表现出长周期特性,均大于10年。1961～2005年间,青藏高原地区整体气候变化以暖湿化趋势为主,暖湿化站点占总数的67%。

This paper analyzed basic characteristics of major climatic factors on the Qinghai-Tibet Plateau during 1961～2005.The result are shown as follows.In the past 45 years,the annual mean temperature was on the rise,with a rate of 0.265℃/10a.The warming tendency in winter was remarkable and that in spring was faint.The temperature rise from 1980 to 2005 was higher than that from 1961 to 1980 and from 1961 to 2005,indicating that there has been a warming trend since the 1980s.In the 45-year period,the annual mean precipitation on the Qinghai-Tibet Plateau was on the faint rise,with a rate of 8.21 mm/10a;annual mean precipitation from 1961 to 1975 was below the average,that from 1975 to 1989 held the line and that after 1990s above the average.Generally speaking,precipitation in spring and winter tended to increase,but the tendency in spring was far greater than that in winter.Annual mean precipitation showed a certain periodicity.At 32 sites on the Qinghai-Tibet Plateau existed a 2～4a short cycle,at 11 sites a 5～8a medium cycle and at 6 sites a long cycle of above 10a.From 1961 to 2005 climatic synthetic tendency was mainly warming-wetting,with sites accounting for 67% of the all.