Following a high-end projection for mass loss from the Greenland and Antarctic ice-sheets, a freshwater forcing was applied to the ocean surface in the coupled climate model EC-Earthv2.2 to study the response to meltwater release assuming an RCP8.5 emission scenario. The meltwater forcing results in an overall freshening of the Atlantic that is dominated by advective changes, strongly enhancing the freshening due to dilution by Greenland meltwater release. The strongest circulation change occurs in the western North Atlantic subpolar gyre and in the gyre in the Nordic Seas, leaving the North Atlantic subpolar gyre the region where most advective salt export occurs. Associated with counteracting changes in both gyre systems, the response of the Atlantic Meridional Overturning Circulation is rather weak over the 190 years of the experiment; it reduces with only 1 Sv (\(= 10^6\) m \(^3\)s \(^{-1}\)), compared to changes in the subpolar gyre of 5 Sv. This relative insensitivity of the AMOC to the forcing is attributed to enhanced convection in the Nordic Seas and stronger overflows that compensate reduced convection in the Labrador and Irminger Seas, and lead to higher sea surface temperatures (SSTs) in the former and lower SSTs in the latter region. The weakened subpolar gyre in the west also shifts the North Atlantic Current and the subpolar-subtropical gyre boundary; with the subtropical gyre expanding, and the western subpolar gyre contracting. The SST changes are associated with obduction of Atlantic waters in the Nordic Seas that would otherwise obduct in the western subpolar gyre. The anomalous SSTs also induce a coupled ocean-atmosphere feedback that further strengthens the Nordic Seas circulation and weakens the western subpolar gyre. This occurs because the anomalous SST-gradient enhances the westerlies, especially between 65\(^{\circ }\)N and 70\(^{\circ }\)N; the associated increase in windstress curl consequently enhances the gyre in the Nordic Seas. This feedback is driven by the Greenland mass loss; Antarctic meltwater discharge causes a weaker, opposite response and more particularly affects the South Atlantic salinity budget through northward advection of low-salinity waters from the Southern Ocean. This effect, however, becomes visible only hundred years after the onset of Antarctic mass loss. We conclude that the response to freshwater forcing from both ice caps can lead to a complex response in the Atlantic circulation systems with opposing effects in different subbasins. The relative strength of the response is time-dependent and largely governed by internal feedbacks; the forcing acts mainly as a trigger and is decoupled from the response.

根据格陵兰和南极冰盖质量损失的高端预测，在耦合气候模型 EC-Earthv2.2 中对海洋表面施加淡水强迫，以研究假设 RCP8.5 排放时对融水释放的响应设想。融水强迫导致大西洋整体变淡，主要是对流变化，由于格陵兰融水释放的稀释，强烈增强了变淡。最强烈的环流变化发生在西北大西洋次极地环流和北欧海的环流中，使北大西洋次极地环流成为发生平流盐出口最多的区域。与抵消两个环流系统的变化有关，大西洋经向翻转环流的响应在 190 年的实验中相当微弱；\(= 10^6\) m \(^3\) s \(^{-1}\))，与 5 Sv 的副极地环流的变化相比。AMOC 对强迫的这种相对不敏感归因于北欧海的对流增强和更强的溢流补偿了拉布拉多海和伊尔明格海的对流减少，并导致前者的海面温度 (SST) 较高，而后者的 SST 较低。后一个地区。西部减弱的副极地环流也改变了北大西洋洋流和副极地-副热带环流边界；副热带环流扩大，西次极地环流收缩。SST 变化与北欧海中大西洋水域的外倾有关，否则这些水域将在西次极地环流中外倾。异常的海温还会引起海洋-大气耦合反馈，进一步加强北欧海环流并削弱西部次极地环流。这是因为异常的 SST 梯度增强了西风带，特别是在 65\(^{\circ }\) N 和 70 \(^{\circ }\)否；风应力卷曲的相关增加因此增强了北欧海域的环流。这种反馈是由格陵兰岛质量损失驱动的；南极融水排放导致较弱、相反的反应，尤其是通过来自南大洋的低盐度海水向北平流影响南大西洋盐度收支。然而，这种影响在南极质量开始减少一百年后才显现出来。我们得出的结论是，对来自两个冰盖的淡水强迫的响应会导致大西洋环流系统中的复杂响应，在不同的子流域中产生相反的影响。响应的相对强度取决于时间，主要受内部反馈控制；强制主要作为触发器，与响应分离。