On the Effect of Historical SST Patterns on Radiative Feedback
On the Effect of Historical SST Patterns on Radiative Feedback
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DOI：
10.1029/2022jd036675
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发表时间：
2022-09-27
影响因子：
4.4
通讯作者：
Liu, Chunlei
中科院分区：
文献类型：
--
作者：
Andrews, Timothy;Bodas-Salcedo, Alejandro;Liu, Chunlei
我们研究了 14 个大气环流模型 (AGCM) 中辐射反馈对海面温度 (SST) 变化模式的依赖性，这些模型是根据从 1871 年到近现代的历史记录中观测到的海表温度和海冰变化而得出的。我们发现，在 1871 年至 1980 年期间，地球变暖的反馈与长期气候敏感性反馈基本一致且密切相关（根据相应的大气-海洋 GCM 突变 4xCO2 模拟诊断）。然而，1980年后，地球变暖，热带太平洋海温异常趋势（西部变暖加剧，东部变冷）和南大洋变冷，导致气候反馈与长期二氧化碳增加的预期不相关，并且表明气候敏感性远低于预期。我们表明，这些结论并不强烈依赖于用于强制 AGCM 的大气模式比对项目 (AMIP) II 海表温度数据集，尽管 1980 年之后使用替代 HadISST1 海表温度边界条件强制的 9 个 AGCM 中的反馈幅度通常较小。我们量化了“模式效应”（定义为历史和长期 CO2 反馈之间的差异）等于 0.48 +/- 0.47 [5%-95%] W m(-2) K-1，当 AGCM 被迫使用 HadISST1 SST 时，1871-2010 年期间，或 0.70 +/- 0.47 [5%-95%] W m(-2) K-1当强制使用 AMIP II SST 时。评估的地球历史能源预算变化与 AGCM 反馈估计一致。此外，自 1985 年以来对大气层顶部辐射通量变化的卫星观测表明，这种模式效应在近几十年来特别强烈，但在 2014 年之后可能会减弱。
We investigate the dependence of radiative feedback on the pattern of sea-surface temperature (SST) change in 14 Atmospheric General Circulation Models (AGCMs) forced with observed variations in SST and sea-ice over the historical record from 1871 to near-present. We find that over 1871-1980, the Earth warmed with feedbacks largely consistent and strongly correlated with long-term climate sensitivity feedbacks (diagnosed from corresponding atmosphere-ocean GCM abrupt-4xCO2 simulations). Post 1980, however, the Earth warmed with unusual trends in tropical Pacific SSTs (enhanced warming in the west, cooling in the east) and cooling in the Southern Ocean that drove climate feedback to be uncorrelated with-and indicating much lower climate sensitivity than-that expected for long-term CO2 increase. We show that these conclusions are not strongly dependent on the Atmospheric Model Intercomparison Project (AMIP) II SST data set used to force the AGCMs, though the magnitude of feedback post 1980 is generally smaller in nine AGCMs forced with alternative HadISST1 SST boundary conditions. We quantify a "pattern effect" (defined as the difference between historical and long-term CO2 feedback) equal to 0.48 +/- 0.47 [5%-95%] W m(-2) K-1 for the time-period 1871-2010 when the AGCMs are forced with HadISST1 SSTs, or 0.70 +/- 0.47 [5%-95%] W m(-2) K-1 when forced with AMIP II SSTs. Assessed changes in the Earth's historical energy budget agree with the AGCM feedback estimates. Furthermore satellite observations of changes in top-of-atmosphere radiative fluxes since 1985 suggest that the pattern effect was particularly strong over recent decades but may be waning post 2014.