Diverse Responses of Global‐Mean Surface Temperature to External Forcings and Internal Climate Variability in Observations and CMIP6 Models
Diverse Responses of Global‐Mean Surface Temperature to External Forcings and Internal Climate Variability in Observations and CMIP6 Models
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DOI：
10.1029/2021gl093194
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发表时间：
2021-08
影响因子：
5.2
通讯作者：
H. Rashid
中科院分区：
文献类型：
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作者：
H. Rashid
我们研究了外部强迫和内部气候变率（ICV）对全球平均地面气温（GMST）变化的影响（1850-2014）观测和第六次耦合模式相互比较项目（CMIP 6）历史模拟的集合。使用多元回归模型，我们估计观测到的GMST方差的83%可以由全球尺度的人为强迫解释。大多数CMIP 6模型低估了这一人为贡献（解释方差的中位数为67%），但当北大西洋区域贡献包括在人为强迫中时（中位数为77%），与观测结果相比更好。ICV对GMST方差的贡献对于观察值为0.8%，对于模型为0.7%（中位数）。模型对外部强迫和ICV的GMST响应差异很大，两者的响应是相反的关系。北大西洋主要驱动观测中的自由GMST变率，而太平洋在大多数CMIP 6模式中驱动这一变率，因为模拟的GMST-太平洋ICV关系比观测到的更强。
We investigate the impacts of external forcings and internal climate variability (ICV) on global‐mean surface air temperature (GMST) variations (1850–2014) in observation and an ensemble of sixth Coupled Model Intercomparison Project (CMIP6) historical simulations. Using multiple regression models, we estimate that 83% of the observed GMST variance is explained by global‐scale anthropogenic forcing. Most CMIP6 models underestimate this anthropogenic contribution (median explained variance is 67%), but compare better with observation when the North Atlantic regional contribution is included in the anthropogenic forcing (median 77%). The ICV contributions to the GMST variance are ∼8% for observation and ∼7% for the models (median). The models' GMST responses to the external forcings and ICV vary widely, with the two responses being oppositely related. The North Atlantic predominantly drives the free GMST variability in observations, whereas the Pacific drives this in most CMIP6 models due to stronger than observed simulated GMST‐Pacific ICV relationships.