CMIP6模式对亚洲陆地生态系统的模拟评估与预估

CMIP6 evaluation and projection of terrestrial ecosystem over Asia

基于国际耦合模式比较计划第六阶段(CMIP6)模式模拟以及观测数据,评估了9个CMIP6模式对亚洲地区叶面积指数(LAI)、总初级生产力(GPP)和净初级生产力(NPP)的模拟性能。模拟评估结果表明,9个CMIP6模式能够较好地模拟出亚洲地区陆地生态系统LAI、GPP和NPP的时空分布特征。综合来看,多模式集合(MME)模拟效果最佳,其模拟的LAI、GPP和NPP与观测的空间相关系数分别达到0.90、0.81和0.89,均方根误差在0.5左右。在此基础上,利用MME结果进一步预估了亚洲地区陆地生态系统在SSP1-2.6、SSP2-4.5和SSP5-8.5情景下的未来变化。总体而言,亚洲地区LAI、GPP和NPP到21世纪末都呈现上升趋势。其中,温室气体高排放情景下的上升趋势大于温室气体低排放情景下的上升趋势,亚洲中高纬度地区的增幅大于低纬度地区的增幅。从区域平均来看,到21世纪末期,与当今气候态相比,北亚LAI、GPP和NPP的增幅最大,其在SSP5-8.5情景下分别增加68%、106%和90%;东南亚增幅最小,分别为15%、34%和39%。在SSP1-2.6情景下,北亚LAI、GPP和NPP在21世纪末的增幅分别为23%、29%和26%;东南亚分别为3%、10%和11%,意味着未来全球变暖背景下亚洲区域陆地生态系统变绿和固碳幅度加强。

Based on the simulations of 9 CMIP6 models and observation data,the performance of the CMIP6 models in simulating the terrestrial leaf area index(LAI),gross primary productivity(GPP)and net primary productivity(NPP)over Asia is evaluated in this paper.The evaluation results indicate that the CMIP6 models can reasonably reproduce the temporal and spatial characteristics of LAI,GPP and NPP over Asia.Moreover,the multi-model ensemble mean(MME)simulation outperforms the individual models.The spatial correlation coefficient between the MME simulated and observed LAI,GPP and NPP are 0.90,0.81 and 0.89,respectively,and the root-mean-square error of the MME simulation with respect to the observation is around 0.5.On this basis,the changes of LAI,GPP and NPP over Asia under the SSP1-2.6,SSP2-4.5 and SSP5-8.5 scenarios are further projected.In general,the MME projections show an increasing trend by the end of the 21st century for the LAI,GPP and NPP over Asia,with larger increases under high emission scenario than under low emission scenario and larger increases over the mid-high latitudes than over the low latitudes of Asia.Regionally averaged,the largest increases in LAI,GPP and NPP by the end of the 21st century are expected in North Asia,where the LAI,GPP and NPP are projected to increase by 68%,106%and 90%under SSP5-8.5 and by 23%,29%and 26%under SSP1-2.6,respectively.The smallest changes are anticipated in Southeast Asia,where the projected increases in LAI,GPP and NPP are 15%,34%and 39%under SSP5-8.5 and 3%,10%and 11%under SSP1-2.6,respectively.These results signify a greening of Asian ecosystem and a strengthening of carbon sequestration in the context of future global warming.