Sensitivity of radiative forcing, ocean heat uptake, and climate feedback to changes in anthropogenic greenhouse gases and aerosols
Sensitivity of radiative forcing, ocean heat uptake, and climate feedback to changes in anthropogenic greenhouse gases and aerosols
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DOI：
10.1002/2015jd023364
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发表时间：
2015-10
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通讯作者：
D. Paynter;T. Frölicher
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作者：
D. Paynter;T. Frölicher
我们使用规定的海洋表面温度和完全耦合版本的地球物理流体动力学实验室耦合气候模式（CM 3）来分析辐射强迫，海洋热吸收和气候反馈的敏感性，分别考虑在1870年至2005年期间的人为温室气体和气溶胶的变化。全球人为气溶胶气候反馈参数（− α）为−1.13 ± 0.33 Wm−2 K−1，与温室气体− α为−1.28 ± 0.23 Wm−2 K−1无法区分。然而，这个温室气体气候反馈参数是约50%，大于CM 3从一个广泛使用的线性外推法回归地球的大气层顶的不平衡对地表空气温度变化的理想化CO2辐射强迫实验。这意味着1870-2005年期间由于强迫引起的全球平均地表温度变化比使用理想化实验获得的气候反馈参数预测的小50%。这种差异是由α的时间依赖性造成的，这使得固定海表温度方法获得的辐射强迫与CO2增加四倍后前150年拟合的线性外推方法获得的辐射强迫不一致。在区域尺度上，温室气体和气溶胶情况下的α变化很大。这表明，瞬态和平衡的气候敏感性之间的关系，从理想化的CO2模拟，使用技术，如区域反馈分析和热吸收效率，可能不适用于其他强迫情景。
We use both prescribed sea surface temperature and fully coupled versions of the Geophysical Fluid Dynamics Laboratory coupled climate model (CM3) to analyze the sensitivity of radiative forcing, ocean heat uptake, and climate feedback to changes in anthropogenic greenhouse gases and aerosols considered separately over the 1870 to 2005 period. The global anthropogenic aerosol climate feedback parameter (− α) of −1.13 ± 0.33 Wm−2 K−1 is indistinguishable from the greenhouse gas − α of −1.28 ± 0.23 Wm−2 K−1. However, this greenhouse gas climate feedback parameter is about 50% larger than that obtained for CM3 from a widely used linear extrapolation method of regressing Earth's top of atmosphere imbalance against surface air temperature change in idealized CO2 radiative forcing experiments. This implies that the global mean surface temperature change due to forcing over the 1870–2005 period is 50% smaller than that predicted using the climate feedback parameter obtained from idealized experiments. This difference results from time dependence in α, which makes the radiative forcing obtained by the fixed sea surface temperature method incompatible with that obtained by the linear extrapolation method fitted over the first 150 years after CO2 is quadrupled. On a regional scale, α varies greatly between the greenhouse gas and aerosol case. This suggests that the relationship between transient and equilibrium climate sensitivities obtained from idealized CO2 simulations, using techniques such as regional feedback analysis and heat uptake efficacy, may not hold for other forcing scenarios.