Collaborative Research: Are There Natural Climate Cycles in the Holocene Variations of Arctic Sea Ice and Greenland Icebergs Across the Denmark Strait?

历史观察和理论表明，通过半球反照率的变化以及北冰洋和格陵兰冰盖的淡水输出对温盐环流的影响，漂流冰的范围和持续时间对气候系统具有重要意义。提供资金用于编制50-100年北冰洋海冰出口变化的分辨率记录，以及从到达丹麦海峡的东北格陵兰潮水冰流运输冰山的变化，并编制过去12,000卡尔·BP的冰筏碎片的详细历史。丹麦海峡被认为是一个关键的研究区域，因为它位于向南出口极地和北极水域与以伊明格海流形式存在的北大西洋漂流西北部之间的边界。这项研究将探索沿格陵兰东南部大陆架和丹麦海峡从源到汇的模型，利用沉积物特征记录丹麦海峡两侧和东北格陵兰大陆架一系列测年准确的高分辨率岩心成分的时空变化。这些信息将被用来推断通过丹麦海峡的海冰运输的变化。鉴于对北极海冰性质变化的持续观测，流入格陵兰-挪威海和北大西洋的海冰流量的变化，以及格陵兰冰盖可能通过冰山崩解而加速融化，更好地了解这些过程在过去是如何变化的，将有助于为未来气候变化的预测提供信息。该项目将开发有助于这一理解的数据集。

Historical observations and theory suggest the importance of the extent and duration ofdrift ice on the Climate System through changes in the Hemispheric albedo and the impact of freshwater export from the Arctic Ocean and Greenland Ice Sheet on the Thermohaline Circulation. Funds are provided to develop 50-100 yr resolution records of changes in sea ice export from the Arctic Ocean and iceberg transport from tidewater ice streams of NE Greenland that reach the Denmark Strait and to develop a detailed history of ice-rafted debris (IRD) over the last 12,000 cal yr BP. Denmark Strait is believed to be a critical area for study as it lies at the boundary between the southward export of Polar and Arctic waters and the northwestern limb of the North Atlantic Drift in the form of the Irminger Current. The research will explore a sources-to-sink model along the ENE/E Greenland shelf and across the Denmark Strait using sediment characteristics to document spatial and temporal changes in composition in a series of well-dated, high-resolution cores from either side of the Denmark Strait and along the NE Greenland shelf. This information will be used to infer changes in the transport of sea ice through the Denmark Strait.Given the ongoing observations of changing sea ice character in the Arctic, changes in the flux of sea ice into the Greenland-Norwegian Seas and the North Atlantic Ocean, and possible acceleration of ice loss from the Greenland Ice Sheet through iceberg calving, a better understanding of how these processes varied in the past will help inform projections of future climate variations. This project will develop data sets that contribute to that understanding.