降水对青藏高原风火山地区多年冻土的影响

Influence of Precipitation on Permafrost in Fenghuo Mountain Region of Tibetan Plateau

收集了青藏高原多年冻土腹部地区风火山冻土定位观测站观测的1976—2014年的年平均气温、年平均地表温度、年降水量及天然冻土测温孔地温资料,对比分析了年平均气温、年平均地表温度、年降水量及多年冻土地温的变化规律及其之间的相互影响关系。结果表明:(1)对于青藏高原风火山地区,寒季降水对多年冻土的保温作用相对较弱,而暖季降水对多年冻土的降温作用相对较强,总体上降水对多年冻土起到了保护作用。(2)在气温和地表温度总体处于升高状态的影响下,青藏高原风火山地区多年冻土地温也在升高,处于退化状态,但降水量的增大降低地表温度,使得传入下部多年冻土的热量减小,从而降低多年冻土地温的升温速率,起到了减缓多年冻土退化的效果。

The data on the annual mean air temperature(AMAT),the annual mean ground surface temperature(AMST),the annual precipitation(AP)and the permafrost ground temperature from 1976 to 2014 in Fenghuo Mountain Permafrost Observational Station were collected.The interaction relationship of the AMAT,AMST,AP and permafrost ground temperature was analyzed.The results show that:(1)the precipitation in cold season has a relatively weak insulation effect on the permafrost of Tibetan Plateau,while the precipitation in warm season has a relatively strong cooling effect on the permafrost.Overall,the precipitation plays a cooling effect on the permafrost.(2)Under the influence of increasing AMAT and AMST,the ground temperature of the permafrost in Fenghuo Mountain region of Tibetan plateau is on the rise and the permafrost is in a state of degradation.However,the increase of precipitation can reduce the ground surface temperature,which reduces the heat transferred to the lower part of the permafrost,thereby reducing the temperature rising rate of the permafrost,and slowing down the degradation of the permafrost.