Tropospheric Adjustment Induces a Cloud Component in CO2 Forcing
Tropospheric Adjustment Induces a Cloud Component in CO2 Forcing
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DOI：
10.1175/2007jcli1834.1
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发表时间：
2008
影响因子：
4.9
通讯作者：
J. Gregory;M. Webb
中科院分区：
文献类型：
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作者：
J. Gregory;M. Webb
在大气CO_2浓度倍增后，通过将年平均全球平均大气顶辐射通量与年平均全球平均地表气温变化ΔT进行回归，在几个具有板状海洋的气候模式中评估了CO_2的辐射强迫和气候反馈参数。该方法表明，在许多模式中，对流层对CO2有显著的快速调整，导致云的变化，并减少有效辐射强迫，类似于气溶胶的间接和半直接影响。相比之下，在大多数模式中，云反馈很小，定义为随ΔT演变的变化的一部分。与通过固定海面条件评估的强迫相比较，无论是全球还是局部，强迫的云成分都给出了定性相似的结果。对流层对二氧化碳的调整可能是一些模式传播平衡气候敏感性的原因，并可能影响依赖于时间的气候预测。
Abstract The radiative forcing of CO2 and the climate feedback parameter are evaluated in several climate models with slab oceans by regressing the annual-mean global-mean top-of-atmosphere radiative flux against the annual-mean global-mean surface air temperature change ΔT following a doubling of atmospheric CO2 concentration. The method indicates that in many models there is a significant rapid tropospheric adjustment to CO2 leading to changes in cloud, and reducing the effective radiative forcing, in a way analogous to the indirect and semidirect effects of aerosol. By contrast, in most models the cloud feedback is small, defined as the part of the change that evolves with ΔT. Comparison with forcing evaluated by fixing sea surface conditions gives qualitatively similar results for the cloud components of forcing, both globally and locally. Tropospheric adjustment to CO2 may be responsible for some of the model spread in equilibrium climate sensitivity and could affect time-dependent climate projections.