Three-dimensional distribution of permafrost and responses to increasing air temperatures in the head waters of the Yellow River in High Asia

摘要

Fine scale three-dimensional (3D) permafrost distributions at the basin scale are currently lacking. They are needed to monitor climatic and ecosystem change and for the maintenance of infrastructure in cold regions. This paper determined the horizontal and vertical distributions of permafrost and its quantitative responses to climate warming in the High Asia region by constructing a quasi-3D model that couples heal transfer and water movement and is forced by spatially-interpolated air temperatures using an elevation-dependent regression method. Four air temperature scenarios were considered: the present stale and air temperature increases of 1, 2 and 3 degrees C A fine-scale permafrost map was constructed. The map considered taliks and local factors including elevation, slope and aspect, and agreed well with field observations. Permafrost will experience severe degradation with climate warming, with decreases in area of 36% per degree increase in air temperature, increases in the depth-to-permafrost table of 2.67 m per degree increase in air temperature, and increases in 15 m-depth ground temperatures of 125 degrees C per degree 'increase in air temperature. Permafrost is more vulnerable in and beside river valleys than in high mountains, and on sunny rather than shady slopes. These results provide an effective reference for permafrost prediction and 'infrastructure and ecosystem management in cold regions affected by global warming. (C) 2019 Elsevier B.V. All rights reserved.