Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, Bremerhaven 27570, Germany.
Nat Commun. 2017 Jun 5;8:15681. doi: 10.1038/ncomms15681.
High latitude ocean gateway changes are thought to play a key role in Cenozoic climate evolution. However, the underlying ocean dynamics are poorly understood. Here we use a fully coupled atmosphere-ocean model to investigate the effect of ocean gateway formation that is associated with the subsidence of the Greenland-Scotland Ridge. We find a threshold in sill depth (∼50 m) that is linked to the influence of wind mixing. Sill depth changes within the wind mixed layer establish lagoonal and estuarine conditions with limited exchange across the sill resulting in brackish or even fresher Arctic conditions. Close to the threshold the ocean regime is highly sensitive to changes in atmospheric CO and the associated modulation in the hydrological cycle. For larger sill depths a bi-directional flow regime across the ridge develops, providing a baseline for the final step towards the establishment of a modern prototype North Atlantic-Arctic water exchange.
高纬度海洋通道的变化被认为在新生代气候演化中起着关键作用。然而，其背后的海洋动力学仍不清楚。在这里，我们使用完全耦合的大气-海洋模式来研究与格陵兰-苏格兰海脊沉降相关的海洋通道形成的影响。我们发现，一个与风混合有关的浅滩深度（约 50 米）的阈值。在风混合层内的浅滩深度变化建立了泻湖和河口条件，限制了通过浅滩的交换，导致微咸甚至更淡的北极条件。接近阈值时，海洋状态对大气 CO 的变化及其对水文循环的调节非常敏感。对于更大的浅滩深度，脊上的双向流模式发展起来，为最终建立现代原型北大西洋-北极水交换奠定了基础。
