Mechanisms and Impacts of a Partial AMOC Recovery Under Enhanced Freshwater Forcing
Mechanisms and Impacts of a Partial AMOC Recovery Under Enhanced Freshwater Forcing
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DOI：
10.1029/2018gl080442
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发表时间：
2019-03
影响因子：
5.2
通讯作者：
Matthew D. Thomas;Alexey V. Fedorov
中科院分区：
文献类型：
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作者：
Matthew D. Thomas;Alexey V. Fedorov
大西洋经向翻转环流（AMOC）预计将减弱，在世纪由于增加表面浮力。海洋模式中的这种AMOC变化通常伴随着密度的地下减少。在这里，我们用1°耦合模式和理想化的纬向平均海洋模式进行淡水扰动实验，以证明缓慢的地下性质变化（1）引入负反馈，侵蚀分层并部分恢复对流和AMOC，（2）确保对流热传输减弱小于AMOC。在格陵兰岛周围引入0.1 Sv净淡水通量的耦合模型中，40年内AMOC最初减少22%，400年后几乎恢复了损失强度的一半。然而，最终的热传输仅减弱了7%。理想化模型中的类似响应表明，二维海洋动力学控制着这些变化。
The Atlantic Meridional Overturning Circulation (AMOC) is expected to weaken in the 21st century due to increased surface buoyancy. Such AMOC changes in ocean models are often accompanied by a subsurface reduction in density. Here we perform freshwater perturbation experiments with both a 1° coupled model and an idealized zonally averaged ocean‐only model to demonstrate that slow subsurface property changes (1) introduce a negative feedback that erodes the stratification and partially reinvigorates convection and the AMOC and (2) ensure the meridional heat transport weakens less than the AMOC. In the coupled model with a 0.1‐Sv net freshwater flux introduced around Greenland, an initial 22% AMOC reduction over 40 years is followed by a recovery of almost half the lost strength after 400 years. The final heat transport, however, is weakened by only 7%. Similar responses in the idealized model demonstrate that 2‐D ocean‐only dynamics control the changes.