Numerical simulation indicates that the future thermal regime of permafrost on Qinghai-Xizang Plateau will change as the air temperature continuously rises at 0.04℃/a. The calculated results show that when Ts are 0, ...Numerical simulation indicates that the future thermal regime of permafrost on Qinghai-Xizang Plateau will change as the air temperature continuously rises at 0.04℃/a. The calculated results show that when Ts are 0, -0.5, -1.5, -2.5, -3.5 and - 4.5℃ under equilibium between climate and permafrost thermal regime, the mean annual temperatures at the depth of 14 m correspondingly equal to -0.11, -0.59, -1.52, -2.45, -3.21 and -4.32℃, and the permafrost thicknesses respectively equal to 16.8, 29.0, 54.1, 79.4, 112.1 and 131.0m. 50 years later, the temperatures at the depth of 14m will rises to 0.0, 0.0, -0.36, -1.23, -2.16, -3.06℃ under the given condition. When TS is lower than -1.1℃, the permafrost will respectively change from initial 2.0, 1.8, 1.6, 1.4m to 2.2, 2.0, 1.8, 1.6m for TS=-1.5, -2.5. - 3.5 and -4.5℃. If TS is higher than - 1.1℃, the frozen ground will change from the attachment type of frozen ground into the detachment type of frozen ground. Therefore, if future air temperature rises at 0.04℃ a or lower, the decrease area of the permafrost on Qinghai-Xizang Plateau may not be over 30℃. The areas includes those changing from the attachment of frozen ground into the detachment of frozen ground. If the area of detachment of frozen ground is not included, the decrease area may only be 3℃ within 50 a.展开更多
Based on the CMIP5 simulation and numerical model, the permafrost thermal regime<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Ve...Based on the CMIP5 simulation and numerical model, the permafrost thermal regime<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> over Northern Hemisphere land during the early (2016-2035), middle (2046-2065) and late (2080-2099) period of 21st century are projected, and its relationship with climate change is also analyzed. The results show that, relative to the reference period of 1986-2005, the mean annual ground temperature (MAGT) over Northern Hemisphere shows an increasing trend, with a decreasing trend of the depth of zero annual amplitude (DZAA), and the most significant changes occur in Siberia, Tibetan Plateau, Canada arctic and Alaska, and the changes in MAGT and DZAA grow larger with time and emission, especially during the LP for RCP8.5, MAGT will increase by 4 </span></span></span><img src="Edit_55a9f4c6-dee0-46dd-b23f-879061d86c00.png" alt="" /><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-size:10.0pt;font-family:;" "=""></span> and DZAA decrease</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> by 1.5</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">m (the relative change exceeds 20%) in most regions. The changes of permafrost in the 21st century mainly depend on the changes of cold permafrost. The relationship between MAGT and air temperature as well as that between DZAA and air temperature suggests that the increase of MAGT and the decrease of DZAA are related to the increase of air temperature in win展开更多
文摘Numerical simulation indicates that the future thermal regime of permafrost on Qinghai-Xizang Plateau will change as the air temperature continuously rises at 0.04℃/a. The calculated results show that when Ts are 0, -0.5, -1.5, -2.5, -3.5 and - 4.5℃ under equilibium between climate and permafrost thermal regime, the mean annual temperatures at the depth of 14 m correspondingly equal to -0.11, -0.59, -1.52, -2.45, -3.21 and -4.32℃, and the permafrost thicknesses respectively equal to 16.8, 29.0, 54.1, 79.4, 112.1 and 131.0m. 50 years later, the temperatures at the depth of 14m will rises to 0.0, 0.0, -0.36, -1.23, -2.16, -3.06℃ under the given condition. When TS is lower than -1.1℃, the permafrost will respectively change from initial 2.0, 1.8, 1.6, 1.4m to 2.2, 2.0, 1.8, 1.6m for TS=-1.5, -2.5. - 3.5 and -4.5℃. If TS is higher than - 1.1℃, the frozen ground will change from the attachment type of frozen ground into the detachment type of frozen ground. Therefore, if future air temperature rises at 0.04℃ a or lower, the decrease area of the permafrost on Qinghai-Xizang Plateau may not be over 30℃. The areas includes those changing from the attachment of frozen ground into the detachment of frozen ground. If the area of detachment of frozen ground is not included, the decrease area may only be 3℃ within 50 a.
文摘Based on the CMIP5 simulation and numerical model, the permafrost thermal regime<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> over Northern Hemisphere land during the early (2016-2035), middle (2046-2065) and late (2080-2099) period of 21st century are projected, and its relationship with climate change is also analyzed. The results show that, relative to the reference period of 1986-2005, the mean annual ground temperature (MAGT) over Northern Hemisphere shows an increasing trend, with a decreasing trend of the depth of zero annual amplitude (DZAA), and the most significant changes occur in Siberia, Tibetan Plateau, Canada arctic and Alaska, and the changes in MAGT and DZAA grow larger with time and emission, especially during the LP for RCP8.5, MAGT will increase by 4 </span></span></span><img src="Edit_55a9f4c6-dee0-46dd-b23f-879061d86c00.png" alt="" /><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-size:10.0pt;font-family:;" "=""></span> and DZAA decrease</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> by 1.5</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">m (the relative change exceeds 20%) in most regions. The changes of permafrost in the 21st century mainly depend on the changes of cold permafrost. The relationship between MAGT and air temperature as well as that between DZAA and air temperature suggests that the increase of MAGT and the decrease of DZAA are related to the increase of air temperature in win
