Liu Wei, Fedorov Alexey V, Xie Shang-Ping, Hu Shineng
Department of Earth and Planetary Sciences, University of California Riverside, Riverside, CA, USA.
Department of Geology and Geophysics, Yale University, New Haven, CT, USA.
Sci Adv. 2020 Jun 26;6(26):eaaz4876. doi: 10.1126/sciadv.aaz4876. eCollection 2020 Jun.
While the Atlantic Meridional Overturning Circulation (AMOC) is projected to slow down under anthropogenic warming, the exact role of the AMOC in future climate change has not been fully quantified. Here, we present a method to stabilize the AMOC intensity in anthropogenic warming experiments by removing fresh water from the subpolar North Atlantic. This method enables us to isolate the AMOC climatic impacts in experiments with a full-physics climate model. Our results show that a weakened AMOC can explain ocean cooling south of Greenland that resembles the North Atlantic warming hole and a reduced Arctic sea ice loss in all seasons with a delay of about 6 years in the emergence of an ice-free Arctic in boreal summer. In the troposphere, a weakened AMOC causes an anomalous cooling band stretching from the lower levels in high latitudes to the upper levels in the tropics and displaces the Northern Hemisphere midlatitude jets poleward.
虽然预计在人为变暖的情况下，大西洋经向翻转环流（AMOC）会放缓，但AMOC在未来气候变化中的确切作用尚未得到充分量化。在此，我们提出一种方法，即在人为变暖实验中通过从北极北大西洋去除淡水来稳定AMOC强度。该方法使我们能够在全物理气候模型实验中分离出AMOC的气候影响。我们的结果表明，减弱的AMOC可以解释格陵兰岛以南的海洋降温，这类似于北大西洋变暖空洞，以及所有季节北极海冰损失的减少，在北半球夏季无冰北极出现的时间上延迟约6年。在对流层，减弱的AMOC会导致一个异常冷却带，从高纬度的低层延伸到热带的高层，并使北半球中纬度急流向极地移动。
