Abrupt CO2 experiments as tools for predicting and understanding CMIP5 representative concentration pathway projections
Abrupt CO2 experiments as tools for predicting and understanding CMIP5 representative concentration pathway projections
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DOI：
10.1007/s00382-012-1410-4
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发表时间：
2013-02-01
期刊：
影响因子：
4.6
通讯作者：
Andrews, Timothy
中科院分区：
文献类型：
--
作者：
Good, Peter;Gregory, Jonathan M.;Andrews, Timothy
开发了一种快速简单的气候模拟方法，用于预测和帮助理解大气环流模式（GCM）模拟。我们表明，简单的模式准确地再现GCM结果，全球平均地面气温变化和全球平均热量吸收预测9 GCM在第五耦合模式相互比较项目（CMIP 5）。这意味着从理想化的CO2步骤实验中获得的理解适用于与政策相关的情景预测。我们的方法在概念上很简单。它的工作原理是利用气候对直接来自GCM实验的CO2阶跃变化的响应。与辐射强迫从非CO2成分通过适应福斯特和泰勒方法，我们用我们的方法来估计CMIP 5代表性浓度路径（RCP）实验的情况下，不运行的GCM的结果。我们估计RCP对之间的差异，而不是RCP异常相对于工业化前的状态。这给出了更好的结果，因为它更多地利用了可用的GCM预测。的GCM表现出不同的辐射强迫，我们将在简单的模式。我们分析这样完成的RCP预测合奏。1986-2005年和2080-2099年全球气温的集合平均变化（热吸收），对于RCP 8.5：3.8 K（2.3 x 10（24）J）; RCP 6.0：2.3 K（1.6 x 10（24）J）; RCP 4.5：2.0 K（1.6 x 10（24）J）; RCP 2.6：1.1 K（1.3 x 10（24）J）。这些情景的温度和热量吸收的相对扩散（标准差/集合平均值）分别约为0.2和0.15。我们通过与时间相关的比率（RCPx的变化）/（RCP8.5的变化），使用工业化前条件的变化，通过减少排放来量化缓解行动的相对效果。我们发现，缓解对全球平均温度变化和热量吸收的影响是非常相似的，在这些不同的GCM。
A fast simple climate modelling approach is developed for predicting and helping to understand general circulation model (GCM) simulations. We show that the simple model reproduces the GCM results accurately, for global mean surface air temperature change and global-mean heat uptake projections from 9 GCMs in the fifth coupled model inter-comparison project (CMIP5). This implies that understanding gained from idealised CO2 step experiments is applicable to policy-relevant scenario projections. Our approach is conceptually simple. It works by using the climate response to a CO2 step change taken directly from a GCM experiment. With radiative forcing from non-CO2 constituents obtained by adapting the Forster and Taylor method, we use our method to estimate results for CMIP5 representative concentration pathway (RCP) experiments for cases not run by the GCMs. We estimate differences between pairs of RCPs rather than RCP anomalies relative to the pre-industrial state. This gives better results because it makes greater use of available GCM projections. The GCMs exhibit differences in radiative forcing, which we incorporate in the simple model. We analyse the thus-completed ensemble of RCP projections. The ensemble mean changes between 1986-2005 and 2080-2099 for global temperature (heat uptake) are, for RCP8.5: 3.8 K (2.3 x 10(24) J); for RCP6.0: 2.3 K (1.6 x 10(24) J); for RCP4.5: 2.0 K (1.6 x 10(24) J); for RCP2.6: 1.1 K (1.3 x 10(24) J). The relative spread (standard deviation/ensemble mean) for these scenarios is around 0.2 and 0.15 for temperature and heat uptake respectively. We quantify the relative effect of mitigation action, through reduced emissions, via the time-dependent ratios (change in RCPx)/(change in RCP8.5), using changes with respect to pre-industrial conditions. We find that the effects of mitigation on global-mean temperature change and heat uptake are very similar across these different GCMs.