| Consistent with the global climate warming,permafrost in the Qinghai-Tibetan Plateau has experienced widespread degradation including a decrease in permafrost area and the thickness of the permafrost.Widespread permafrost degradation has already caused environmental and hydrological environment problem,which has received much recent attention for the study of global climate change.The study on the changes of permafrost and eco-hydrology response is great of scientific value.Based on the MODIS LST and meteorological surface temperature,Arc GIS builder frost number model is used to simulate the extend of permafrost,to analyze the spatial and temporal variation of permafrost.Based on the annual ground temperature,Arc GIS raster calculator is used to simulate the thickness of permafrost and estimate the volume of ground ice in the permafrost regions and predict the volume of ground ice-melt in the future scenario.Base on the GIMMS NDVI remote sensing date,ENVI IDL is used to investigate the spatial and temporal variation of vegetable coverage in the process of permafrost degradationResult showed that permafrost in the Qinghai-Tibetan Plateau has experienced widespread fluctuation degradation in the 40 years,the decline in permafrost areal extent is from 140×104 km2 in the 1970 s and 1980 s to 120×104 km2 in the 1990 s,and possibly 110×104 km2 in 2000 s.The thickness of permafrost is about 90 m and the volume of ground ice is about 1.08×1013 m3.The thickness of permafrost is about 60 m and the volume of ground ice is about 7.04×1012 m3 in the 100 years later in the scenario of temperature increase of 0.03℃/a,releasing about 7.04×1012 m3,the average annual rate is 7.04×1010 m3/a.The vegetable coverage has different variation trend in the different stage of permafrost degradation.To sum up,.the study is of great value to understanding the eco-hydrology and ecological restoration. |
