青藏铁路工程走廊多年冻土对全球气候变化的响应

Response of Permafrost to Global Climate Change in Engineering Corridor of Qinghai-Tibet Railway

针对受全球气候转暖影响青藏铁路沿线年平均气温逐年上升的环境变化,基于青藏铁路沿线不同区域内多年来的气象及地温监测资料,进行青藏铁路工程走廊气候要素演化及多年冻土对全球气候变化响应的研究。结果表明:青藏铁路工程走廊内气温基本以年均0.03℃的速度升高;年降水量大部分在250~450mm之间,且呈波动增大变化趋势;冻结指数和融化指数逐年增大,暖冬现象明显;地面温度升温速率达0.06℃·年-1,是气温升温速率的1.34倍;沿线多年冻土区2007年至2013年间天然上限抬升的仅占9%,而天然上限下降的占91%;地基多年冻土不同深度处地温均在升高,距离上限较近的地温升温速率普遍最大,多年冻土退化主要为自上而下;唐古拉山以北多年冻土退化较唐古拉山以南明显。

In view of the impact of global climate warming,the annual average temperature along the Qinghai Tibet Railway is rising year by year.Based on the meteorological and ground temperature monitoring data over the years in different regions along the Qinghai-Tibet Railway,the evolution of climatic factors and the response of permafrost to global climate change in the engineering corridor of Qinghai-Tibet Railway are studied.Results show that the temperature in the engineering corridor of the Qinghai Tibet Railway rises by an average of 0.03 ℃.The annual precipitation is mostly between 250-450 mm,and the trend of fluctuation increases.The freezing index and melting index are increasing year by year,and the warm winter phenomenon is obvious.The increase rate of ground temperature reaches0.06 ℃·a^-1,which is 1.34 times of temperature rising rate.From 2007 to 2013,the uplift in the natural upper limit of the permafrost regions along the line accounted for only 9%,while the decline in natural upper limit accounted for 91%.The ground temperatures at different depths of foundation permafrost are increasing.The ground temperature rising rate near the upper limit is generally the maximum.The permafrost degradation is mainly from top to bottom.The permafrost degradation in the north of Tanggula Mountain is more obvious than that in the south of Tanggula Mountain.