The modern and glacial overturning circulation in the Atlantic ocean in PMIP coupled model simulations
The modern and glacial overturning circulation in the Atlantic ocean in PMIP coupled model simulations
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DOI：
10.5194/cp-3-51-2007
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发表时间：
2006-10
影响因子：
4.3
通讯作者：
S. Weber;S. Drijfhout;A. Abe‐Ouchi;M. Crucifix;M. Eby;A. Ganopolski;Shingo Murakami;B. Otto‐Bliesner;W. Peltier
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文献类型：
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作者：
S. Weber;S. Drijfhout;A. Abe‐Ouchi;M. Crucifix;M. Eby;A. Ganopolski;Shingo Murakami;B. Otto‐Bliesner;W. Peltier
本文分析了九个PMIP耦合模式模拟中大西洋经向翻转环流(AMOC)对LGM强迫和边界条件的响应，其中包括GCMS和中等复杂性的地球系统模式。模型结果大相径庭。与现代气候相比，四个模型的AMOC在末次日冕期间显著减慢(20%-40%)，其中一个模型略有下降，四个模型显示AMOC强度大幅增加(10%-40%)。研究发现，南极底层水(AABW)和北大西洋深水(NADW)在源区的密度差异是AMOC响应的一个主要控制因素。密度对比度的变化是由温度和盐度变化的相反影响决定的，与NADW相比，AABW的含盐量在所有模型中都是一致的，而AABW的冷却程度在所有模型中都较少，只有一个模型除外。在只有两个模式中，末次盛冰期的AMOC响应与大西洋盆地上净蒸发的响应直接相关。大多数模型显示，进入盆地的海洋淡水输送发生了很大的变化，但这似乎并不影响AMOC的反应。最后，这在一定程度上依赖于控制状态的准确性。
This study analyses the response of the Atlantic meridional overturning circulation (AMOC) to LGM forcings and boundary conditions in nine PMIP coupled model simulations, including both GCMs and Earth system Models of Intermediate Complexity. Model results differ widely. The AMOC slows down considerably (by 20–40%) during the LGM as compared to the modern climate in four models, there is a slight reduction in one model and four models show a substantial increase in AMOC strength (by 10–40%). It is found that a major controlling factor for the AMOC response is the density contrast between Antarctic Bottom Water (AABW) and North Atlantic Deep Water (NADW) at their source regions. Changes in the density contrast are determined by the opposing effects of changes in temperature and salinity, with more saline AABW as compared to NADW consistently found in all models and less cooling of AABW in all models but one. In only two models is the AMOC response during the LGM directly related to the response in net evaporation over the Atlantic basin. Most models show large changes in the ocean freshwater transports into the basin, but this does not seem to affect the AMOC response. Finally, there is some dependence on the accuracy of the control state.