Research on the variation characteristics of active layer thickness of permafrost in the Three River Source Region
The active layer,which is the primary area for permafrost and atmosphere to exchange heat and wa-ter,and its morphological changes have a significant impact on ecosystems,topography and geomorphology,surface and subsurface hydrological processes,carbon cycle,and safety of engineering structures in cold cli-mates.In this paper,the spatial distribution characteristics of active layer thickness in the Three River Source Region(TRSR)and its future changes are studied based on the modified Stefan model,and the factors that may affect the variation of active layer thickness are discussed.The results show that the thickness of active layer has been increasing at a rate of 7.2 cm∙(10a)-1 from 1981 to 2018,and will continue to increase in the future,most significantly in the central part of the TRSR.From 2006 to 2049,the active layer thickness increases at a rate of 4.3 cm∙(10a)-1(RCP6.0)to 6.8 cm∙(10a)-1(RCP8.5);from 2050 to 2099,it increases at a rate of 0.04 cm∙(10a)-1(RCP2.6)to 4.8 cm∙(10a)-1(RCP8.5),which is significantly less than the rate of increase in the pre-vious 50 years.The rate of increase in active layer thickness has slowed down.Analysis of the factors influenc-ing the variation of active layer thickness shows that the greatest influence is on mean annual air temperature,while the influence of annual precipitation is not significant,and NDVI has some influence on active layer thick-ness.This result will have an important impact on the water conservation,climate regulation,and ecological se-curity of the TRSR.
the Three River Source RegionQinghai-Xizang Plateaupermafrostclimate changeactive layer thickness
万方数据
维普
