青藏铁路沿线多年冻土区地温场变化规律

青藏铁路通过约550km的多年冻土区,统计和分析青藏高原多年冻土分布区主要气象台站的资料可以看出,近30a来高原多年冻土区的气候变化总的趋势是向着气温升高的方向发展的,气温的变化对多年冻土热状态的扰动主要表现在地温场的变化上.30多年来高原气温升高0.45℃左右,并引起冻土地温平均升高了0.2～0.3℃.分析青藏铁路通过的多年冻土地区典型地段测温孔资料,发现多年来气候转暖已经使冻土上部(20m以上)地温明显升高,影响深度已经波及到了40m.

Variation of the Ground Temperature Field in Permafrost Regions along the Qinghai-Tibetan Railway

Over 550 km roadbed of the Qinghai-Tibetan Railway is constructed in permafrost Regions. Analyzing the data of main observatories on permafrost regions in the Tibetan Plateau, it is found that the main climate change trend in permafrost regions is increasing in the last 30 years. The change of ground temperature field embodies that climate change influences thermal state of frozen soil. For the 30 years, air temperature in the plateau has increased about 0.45℃, causing the temperature of frozen soil averagely increasing about 0.2～0.3℃. Air temperature increase has obviously influenced the ground temperature down to 20 m deep and has slight effect on the deeper soil. In this paper, analyzing the observed ground temperature data in representative permafrost areas along the Qinghai-Tibetan Railway, it is revealed that the ground temperature of the upper frozen soil has increased with an influence depth of 40 m.