青藏高原风火山地区冻土变化分析

基于对多年来风火山地区的多年冻土资料,研究了天然地区和路基下的冻土上限变化情况以及多年冻土的融化状态,并定量分析了进入多年冻土内的热状况。结果表明：风火山地区从20世纪70年代到90年代中期冻土上限下降,冻土出现退化现象,从90年代至今冻土趋于稳定；路基近地表地温明显高于对应天然地表下的地温,路基近地表经历的融化期长于对应天然地表,进入多年冻土区的热收支也呈现出吸热明显大于放热的周期性变化,进入多年冻土的热积累暂时以增高地温耗热为主,但随着冻土吸热量的逐年积累、冻土温度的不断升高,本区冻土可能发生强烈融化。

Permafrost change in the Fenghuo shan mountain of Qinhai-Tibet Plateau

Based on the several year data of permafrost in the region of Fenghuoshan Mountain,this paper not only studied the transformation of upper limit of permafrost in natural ground and roadbed but also the thawing of permafrost,and analysed quantitatively the status of heat which have entered permafrost.The results demonstrate that the upper limit of permafrost in this area had declined from 1970s to the middle phase of 1990, and permafrost has appeared degenerate tendecy,but since middle 1990s,permafrost have a stable state;ground temperature of roadbed near the earth surface is higher than that of the natural ground,thawing time of roadbed near the earth surface is longer than that of the natural ground,the heat income within the permafrost is greater than the heat release from the permafrost during anannual period,the heat accumulation within the permafrost is temporarily appeared as temperature rising,but with the heat accumulation within permafrost growing up year by year,permafrost temperature will become higher gradually,and strong thawing of permafrost could be happened in the region.