Long run surface temperature dynamics of an A-OGCM: the HadCM3 4×CO2 forcing experiment revisited
Long run surface temperature dynamics of an A-OGCM: the HadCM3 4×CO2 forcing experiment revisited
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A-OGCM 的长期表面温度动态：重新审视 HadCM3 4×CO2 强迫实验
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
A. Jarvis
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文献类型：
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作者：
Sile Li;A. Jarvis
利用传递函数方法分析了HadCM 3模式对1,000年4×CO2强迫的全球平均地表温度（GMST）响应。我们确定了一个三阶传递函数是一个适当的表征辐射强迫输入和GMST输出的大气-海洋环流模式（A-OGCM）之间的动态关系。从这个传递函数的平衡气候敏感性估计为4.62（3.92-11.88）K，这是显着高于以前估计的HadCM 3。响应的时间常数为4.5（3.2-6.4）、140（78-191）和1,476（564- 11737）年。事实上，最长的时间常数元素是显着长于1,000年的模拟运行，使估计这一元素的响应有问题，突出需要显着更长的模型运行，以充分表达A-OGCM的行为。传递函数的解释与三箱全球能量平衡模型。结果发现，这种解释产生了海洋热容量的三个部分，有效深度为63.0（46.7-85.4）、1291.7（787.3- 2 955.3）和2 358.0（661.3- 17，283.8）米的海水，与4.6（3.2-6.5）、107.7（68.9-144.3）和537.1（196.2- 1，243.1）年的三个离散时间常数相关。考虑到这占HadCM 3海洋热容量的94%，从千年时间尺度来看，HadCM 3似乎比以前认为的要混合得更好。
The global mean surface temperature (GMST) response of HadCM3 to a 1,000 year 4×CO2 forcing is analysed using a transfer function methodology. We identify a third order transfer function as being an appropriate characterisation of the dynamic relationship between the radiative forcing input and GMST output of this Atmosphere-Ocean General Circulation Model (A-OGCM). From this transfer function the equilibrium climate sensitivity is estimated as 4.62 (3.92–11.88) K which is significantly higher than previously estimated for HadCM3. The response is also characterised by time constants of 4.5 (3.2–6.4), 140 (78–191) and 1,476 (564–11,737) years. The fact that the longest time constant element is significantly longer than the 1,000 year simulation run makes estimation of this element of the response problematic, highlighting the need for significantly longer model runs to express A-OGCM behaviour fully. The transfer function is interpreted in relation to a three box global energy balance model. It was found that this interpretation gave rise to three fractions of ocean heat capacity with effective depths of 63.0 (46.7–85.4), 1291.7 (787.3–2,955.3) and 2,358.0 (661.3–17,283.8) meters of seawater, associated with three discrete time constants of 4.6 (3.2–6.5), 107.7 (68.9–144.3) and 537.1 (196.2–1,243.1) years. Given this accounts for approximately 94% of the ocean heat capacity in HadCM3, it appears HadCM3 could be significantly more well mixed than previously thought when viewed on the millennial timescale.