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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年里，北大西洋地区发生了一系列明显的千年至百年尺度的海洋和气候振荡。越来越多的证据表明，通过东格陵兰洋流路线的北冰洋淡水平流的变化和格陵兰冰盖的当地融水供应与这些振荡有关，并导致了地表和地下水条件的广泛脱钩。特别是在亚极地的北大西洋，这种解耦是沿着亚极地环流的北/西北边界流记录的，即东格陵兰流和西格陵兰流。然而，关于晚全新世淡水平流通过北冰洋第二主要淡水流出通道——加拿大北极群岛西部，对拉布拉多海流特性产生强烈影响的情况知之甚少。反过来，拉布拉多洋流与东西格陵兰洋流一起影响着亚极地环流，而亚极地环流调节着进入北大西洋北部的热平流，从而影响着北半球的气候条件。由于关于加拿大北极群岛/拉布拉多洋流路线的淡水流出变化的信息有限，我们对北大西洋千年至百年尺度气候变化的理解受到限制。提出的多代理研究结合定性（有孔虫组合）和定量（稳定同位素和微量元素研究、烯酮），首次以高分辨率重建了加拿大东部陆架的海洋沉积物岩心、地表（淡水）和地下水条件。在试点研究中获得的放射性碳定年和放射性核素测量证明，这些在2015年MSM45和46巡航期间收集的岩心，在几十年到百年的尺度上解决了全新世晚期的海洋和气候变化。对从哈德逊海峡到圣劳伦斯湾的加拿大东部大陆架的地表水和地下水性质的多代理调查，将有助于评估全新世晚期海洋变化与北大西洋次极气候变化之间的联系。