Links between subpolar Northwest Atlantic surface to deep ocean variability and Atlantic Meridional Overturning Circulation since the Last Glacial Maximum

亚极西北大西洋作为深水形成的主要区域之一，是大西洋子午线翻转环流(AMOC)的重要组成部分。特别是，冬季表层水的对流导致了拉布拉多海水(LSW)的形成，拉布拉多海水构成了北大西洋深水(NADW)的上肢，并在现代AMOC中发挥了核心作用。几项基于仪器数据的研究表明，亚极地大西洋和拉布拉多海的AMOC因人为变暖和表面清新而减弱。然而，仪器观测仅限于过去几十年，我们对AMOC在千年到多中心时间尺度上的长期变异性和驱动机制的理解仍然不完整。古气候替代记录，例如那些来自海洋沉积物的记录，为在更长的时间尺度上研究北大西洋亚极区过去从表层到深层的海洋变异性提供了一个独特的机会，并获得了我们在变化的气候边界条件下对AMOC行为的理解。在这项研究中，我们将使用一种创新的方法，通过对2014年在玛丽亚·S·梅里安探险MSM39上收集的西北大西洋高分辨率沉积物岩芯的处理，在数百年的时间尺度上重建地表和深水水文地理学。我们将重点关注过去24,000年的时间段，这段时间涵盖了过去与间歇性融水通量事件(海因里希事件)相关的AMOC的重大和突然变化，以进一步研究自然AMOC扰动背后的机制，并得出未来AMOC稳定性和气候的潜在基准。

As one of the main regions of deep-water formation, the subpolar Northwest Atlantic is a crucial component of the Atlantic Meridional Overturning Circulation (AMOC). In particular, wintertime convection of surface waters leads to formation of Labrador Sea Water (LSW) that forms the upper limb of North Atlantic Deep Water (NADW) and plays a central role in the modern AMOC. Several studies based on instrumental data suggest AMOC weakening in response to anthropogenic warming and surface freshening in the subpolar Atlantic and Labrador Sea. However, instrumental observations are temporally limited to the past decades only and our understanding of long-term variability and driving mechanisms of AMOC on millennial- to multicentennial timescales remains incomplete. Paleoclimate proxy records, such as those derived from marine sediments, offer a unique opportunity to investigate past surface to deep ocean variability of the subpolar North Atlantic on much longer timescales and to gain our understanding of AMOC behaviour under changing climate boundary conditions. In this study, we will use an innovative approach via contemporaneous reconstructions of surface and deep-water hydrography on multi-centennial timescales from a transact of NW Atlantic high-resolution sediment cores collected on MARIA S. MERIAN Expedition MSM39 in 2014. We will focus on the last 24,000 cal yr BP, a time period that covers past major and abrupt changes in AMOC related to episodic meltwater flux events (Heinrich Events), to further investigate mechanisms behind natural AMOC perturbations and to derive potential benchmarks for future AMOC stability and climate.