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

自末次盛冰期以来副极地西北大西洋表面与深海变率和大西洋经向翻转环流之间的联系

• 批准号: 395191400
• 负责人: Dr. Lars Max
• 金额: --
• 依托单位: Alfred-Wegener-Institut (AWI) Helmholtz-Zentrum für Polar- und Meeresforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/395191400?language=en
• 关键词: Links; between; subpolar; Northwest; Atlantic

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.

副极地西北大西洋是深水形成的主要区域之一，是大西洋经向翻转环流（AMOC）的重要组成部分。特别是，冬季对流的表面沃茨导致拉布拉多海水（LSW）的形成，形成北大西洋深水（NADW）的上肢，并在现代AMOC中发挥核心作用。基于仪器数据的几项研究表明，在次极地大西洋和拉布拉多海的人为变暖和表面清新的AMOC减弱。然而，仪器观测在时间上仅限于过去几十年，我们对AMOC在千年到数百年时间尺度上的长期变化和驱动机制的理解仍然不完整。古气候代用记录，如来自海洋沉积物的记录，提供了一个独特的机会，以调查过去的表面到深海的变化，在更长的时间尺度上的亚极地北大西洋，并获得我们的了解AMOC的行为在不断变化的气候边界条件。在这项研究中，我们将使用一种创新的方法，通过对在MARIA S上收集的西北大西洋高分辨率沉积物岩心进行的数百年时间尺度的地表和深水水文学的同期重建。MERIAN Expedition MSM 39 2014年我们将专注于过去的24,000 cal yr BP，一个时间段，涵盖了过去的主要和突然的变化，AMOC相关的情节融水通量事件（海因里希事件），进一步研究自然AMOC扰动背后的机制，并获得未来AMOC稳定性和气候的潜在基准。