2000年后全球气温的增温率显著下降,全球进入变暖减缓期。本文基于CRU(Climatic Research Unit) 观测资料,分析讨论了2000年后全球及欧亚中高纬度地区全球变暖的减缓特征,评估了CMIP5(Coupled Model Intercomparison Project Phase 5)试验多模式对全球变暖减缓的模拟及未来气温变化预估。结果表明,2000年后全球陆地平均地面气温的增温率大幅下降至0.14°C (10 a)~(-1),仅为1976~1999年加速期增温率的一半。全球陆地13个区域中有9个地区的增温率小于2000年前,4个地区甚至出现了降温。其中以欧亚中高纬地区最为特殊。加速期(1976~1999年)增温率达到0.50°C (10 a)~(-1),为全球陆地最大,2000年后陡降至-0.17°C (10 a)~(-1),为全球最强降温区,为全球变暖的减缓贡献了49.13%。并且具有显著的季节依赖,减缓期冬季增温率下降了-2.68°C (10 a)~(-1),而秋季升高了0.86°C (10 a)~(-1),呈现反位相变化特征。CMIP5多模式计划中仅BCC-CSM1.1在RCP2.6情景下和MRI-ESM1模式在RCP8.5下的模拟较好地预估了全球及欧亚中高纬地区在2000年后增温率的下降以及欧亚中高纬秋、冬温度的反位相变化特征。BCC-CSM1.1在RCP2.6情景下预估欧亚中高纬地区2012年后温度距平保持在1.2°C左右,2020年后跃至2°C附近振荡。而MRI-ESM1在RCP8.5情景下预估的欧亚中高纬度温度在2030年前一直维持几乎为零的增温率,之后迅速升高。
英文摘要:
The rise in global surface temperature has significantly declined after 2000. In this study, the evolution of the surface temperature of the global land-mean and Eurasia middle-high latitudes during the global warming hiatus was analyzed based on CRU observations. Simulations and projections were also evaluated using the Coupled Model Intercomparison Project 5 (CMIP5). The results indicate that, in the global warming hiatus period, the trend of the global land-mean surface temperature is only 0.14°C (10 a)~(-1), which is half that during 1976-1999. The trend is less than that before 2000 in nine of the 13 global land regions, and four of them show a decreasing trend. The Eurasia middle-high latitude region is the most interesting among all the regions. For 1976-1999, the Eurasia middle-high latitude region shows the largest warming among all the land regions and reaches 0.50°C (10 a)~(-1). After 2000, the trend significantly declines to -0.17°C (10 a)~(-1), the greatest cooling trend over land, globally, contributing 49.13% of the remarkable change in global land surface temperatures before and after 2000. Furthermore, the surface temperature of the Eurasia middle-high latitude region shows an opposite change in autumn and winter after 2000; the temperature of the former rises by 0.86°C (10 a)~(-1), while the that of the latter decreases by 2.68°C (10 a)~(-1). In CMIP5, only the simulation and projects in BCC-CSM1.1 under the RCP2.6 scenario and MRI-ESM1 under the RCP8.5 scenario reproduce the evolution of the global land-mean and Eurasia middle-high latitude surface temperature, as well as the opposite change between autumn and winter of the Eurasia middle-high latitude region, during the global warming hiatus. The temperature projection of the BCC-CSM1.1 under the RCP2.6 scenario for the Eurasia middle-high latitude remains flat, near 1.2°C, after 2012, and jumps to 2°C after 2020. The change in the MRI-ESM1's projected temperature under the RCP8.5 scenario is close to zero before 2030; the temperature then rises remarkably, to °C (10 a)~(-1).