基于CMIP6模式数据的1961—2100年青藏高原地表气温时空变化分析

基于第六次国际耦合模式比较计划（CMIP6）的22个地球气候/系统模式模拟数据，分析了1961—2100年期间青藏高原年均地表气温在不同情景下的时空变化。结果表明，多模式集合平均的模拟结果优于大多数单个模式。由于共享社会经济路径（SSP）和辐射强迫的不同，在SSP1-2.6、SSP2-4.5、SSP3-7.0和SSP5-8.5四种情景下，2015—2100年间青藏高原年均地表气温的增温趋势分别为0.10 ℃·（10a）^-1、0.29 ℃·（10a）^-1、0.53 ℃·（10a）^-1和0.69 ℃·（10a）^-1，帕米尔高原、藏北高原中西部和巴颜喀拉山区为三个升温中心。相对于1995—2014年参考时段，到本世纪中期（2041—2060年），青藏高原区域年均地表气温将分别增加1.37 ℃、1.72 ℃、1.98 ℃和2.30 ℃，而到本世纪末期（2081—2100年），年均地表气温将分别增加1.42 ℃、2.65 ℃、4.28 ℃和5.38 ℃。与《巴黎协定》提出的到本世纪末全球平均气温升高不超过2 ℃目标相比，无论在哪种情景下，到本世纪中期时青藏高原年均地表气温相对于工业革命前均升高超过2 ℃，这会造成极大的气候生态环境问题。

Analysis on spatiotemporal variations of near-surface air temperature over the Tibetan Plateau from 1961 to 2100 based on CMIP6 models'data

Tibetan Plateau is extremely sensitive to global warming because of its unique cryospheric geomorphy， and the warming rate is twice the global average. This research is to study and project the future trend of near-surface air temperature over the Tibetan Plateau under the background of global warming. Based on 22 earth-climate system models’ simulation data from the Coupled Model Intercomparison Project Phase 6 （CMIP6）， the spatial and temporal variations of the annual mean near-surface air temperature over the Tibetan Plateau under different scenarios from 1961 to 2100 are analyzed. These scenarios include the historical （1961—2014） and future （2015—2100） four different shared socioeconomic pathways （SSPs）： SSP1-2.6， SSP2-4.5， SSP3-7.0， and SSP5-8.5. Firstly， the performance of 22 models is evaluated by comparing their outputs with ground observation for the period 1961—2014. The ground observation is from China Meteorological Data Service Centre， including the observation data of 66 meteorological stations with complete time series. Taylor diagram， which reflects correlation coefficient， standard deviation and root mean square error， is used to evaluate the simulation ability of the models. Due to the different resolution between the models， the bilinear interpolation method is used to interpolate the data of each future model （2015—2100） into the 0.5°×0.5° grids， with a total of 1 214 grid points. Then， the future changes of annual mean near-surface air temperature over the Tibetan Plateau are analyzed by using the multi-model ensemble mean results. The results show that： through the analysis of Taylor diagram， it is found that the multi-model ensemble mean usually shows better skill than most of single models. Due to the differences of the SSP and radiative forcing， the warming trend during 2015—2100 is 0.10 ℃·（10a）^-1， 0.29 ℃·（10a）^-1， 0.53 ℃·（10a）^-1 and 0.69 ℃·（10a）^-1 under SSP1-2.6， SSP2-4.5， SSP3-7.0 and SSP5-8.5 scenarios， respectively. The SSP1-2.6 scenario indicates that the annual mean near-surface air temperature over the Tibetan Plateau remains stable after 2050 and shows a slight downward trend， while the other scenarios show a warming trend. Compared with the reference period from 1995 to 2014， the annual mean near-surface air temperature of the plateau will increase by 1.37 ℃， 2.81 ℃， 5.04 ℃ and 6.21 ℃ to 2100， respectively. With the increase of emission scenarios， the warming rate increases. The three warming centers are the Pamirs， midwest part of the northern Tibetan Plateau， and the Bayan Kara Mountains. The regions with the smallest warming trend are concentrated in the southeast of Tibetan Plateau. Compared with 1995—2014， to the middle of this century （2041—2060）， the annual mean near-surface air temperature of the Tibetan Plateau will increase by 1.37 ℃， 1.72 ℃， 1.98 ℃ and 2.30 ℃， respectively. And to the end of this century （2081—2100）， the annual mean near-surface air temperature will increase by 1.42 ℃， 2.65 ℃， 4.28 ℃ and 5.38 ℃， respectively. The future warming range in the same time period is higher than CMIP5 simulation results. Compared with the commitment of Paris Agreement to “holding the increase in the global average temperature to well below 2 ℃ above pre-industrial levels”， through this study， under any scenarios， the annual mean near-surface air temperature over the Tibetan Plateau will increase more than 2 ℃ above pre-industrial levels to the middle of this century. For the Tibetan Plateau with the cryosphere as the main geomorphic feature， it will lead to accelerated melting of glaciers and more frequent extreme weather and climate events， and it is urgent to take corresponding emission reduction measures. This study can provide a reference for the research of climate change on the Tibetan Plateau and provide a scientific basis for the formulation of mitigation strategies. Meanwhile， it also provides reference for the related evaluation and research of CMIP6 models’ results.