Late Holocene multi-decadal to centennial scale oceanic variability on the eastern Canadian shelf linked to North Atlantic climatic changes

全新世晚期加拿大东部陆架数十年至百年规模的海洋变化与北大西洋气候变化有关

基本信息

批准号：
389191347
负责人：
Dr. Kerstin Perner
金额：
--
依托单位：
Leibniz-Institut für Ostseeforschung Warnemünde (IOW)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/389191347?language=en
关键词：
Late Holocene multi decadal centennial

项目摘要

A series of distinct millennial to centennial scale oceanic and climatic oscillations occurred in the North Atlantic region during the last 3000 years. There is increasing evidence that variable freshwater advection from the Arctic Ocean via the East Greenland Current route and local meltwater supply from the Greenland Ice sheet is linked to these oscillations and caused a widespread decoupling of surface and subsurface water conditions. Particularly within the subpolar North Atlantic this decoupling is documented along the N/NW boundary currents of the Subpolar Gyre, i.e. the East Greenland Current, and West Greenland Current. However, little is known concerning the late Holocene freshwater advection via the second major Arctic Ocean freshwater outflow route, the western Canadian Arctic Archipelago, which strongly influences the Labrador Current properties. The Labrador Current, in turn, together with the East and West Greenland Current affects the Subpolar Gyre circulation, which regulates the heat advection into the northern North Atlantic and thus, northern hemisphere climatic conditions. As only limited information on freshwater outflow changes via the Canadian Arctic Archipelago/Labrador Current route is available, our understanding of millennial to centennial scale North Atlantic climate variability is constrained. The proposed multi-proxy study combining qualitative (foraminifer assemblages) and quantitative (stable isotope and trace element studies, alkenones) reconstructs for the first time, from marine sediment cores, surface (freshwater) and subsurface water conditions on the eastern Canadian shelf at a high resolution. Radiocarbon dates and radionuclide measurements, obtained during a pilot study, prove that these cores, collected in 2015 during the MSM45 and 46 cruises, resolve late Holocene oceanic and climatic changes at a multi-decadal to centennial scale. The proposed multi-proxy investigations of surface and subsurface water properties, spanning the eastern Canadian shelf from Hudson Strait to the Gulf of St. Lawrence, will allow assessing the link between oceanic changes, and the subpolar North Atlantic multi-decadal to centennial scale climate variability during the late Holocene.

在过去的3000年中，北大西洋地区发生了一系列独特的千禧一代至百年尺度的海洋和气候振荡。有越来越多的证据表明，通过东格陵兰电流路线从北极海洋中进行可变的淡水对流，而格陵兰冰盖的局部融水供应与这些振荡有关，并引起了表面和地下水条件的广泛脱钩。尤其是在北大西洋亚北大大西洋中，这种去耦被记录在沿着极线回旋的N/NW边界电流，即东格陵兰电流和西格陵兰岛电流。然而，关于通过第二个主要北极海洋淡水流出路线，加拿大西部北极群岛的第二个主要北极淡水流出路线的全新世淡水流的知之甚少，这对拉布拉多的当前特性很大。拉布拉多电流又与东格陵兰电流一起影响了下极循环，该循环会调节北大西洋北部的热量对流，从而调节北半球的气候条件。由于只有通过加拿大北极群岛/拉布拉多的当前路线有限的淡水流出变化信息，因此我们对千禧一代至百年纪念量表北大西洋气候变化的理解受到限制。提出的多种研究研究将定性（有孔虫组合）和定量（稳定的同位素和痕量元素研究，烯烃）首次重建，从海洋沉积物核心，表面（淡水）和地下水条件从高分辨率的东部货架上进行。在试点研究中获得的放射性碳日期和放射性核素测量结果证明，这些核心于2015年在MSM45和46次巡航期间收集，解决了全新世晚期海洋，并以多年代到百年纪念尺度的多年气候变化。从哈德逊海峡到圣劳伦斯海湾的东部加拿大货架，对地面和地下水性质进行了拟议的多种研究，将允许评估海洋变化之间的联系，而北大西洋多人多年群落到全钙期后期的百年纪念量表。