Collaborative Research: Do Holocene Variations In Arctic Sea Ice And Greenland Icebergs Drifting Through Denmark Strait Reflect Natural Cycles?

历史观测和理论表明，通过半球反照率的变化以及北冰洋和格陵兰冰盖淡水输出对温盐环流的影响，漂冰的范围和持续时间对气候系统具有重要意义。提供的资金用于开发50-100年北冰洋海冰输出和格陵兰岛东北部潮汐冰流到达丹麦海峡的冰山运输变化的分辨率记录，并开发过去12,000万年BP的浮冰碎片（IRD）的详细历史。丹麦海峡被认为是一个重要的研究区域，因为它位于极地和北极水域向南出口和北大西洋漂流西北分支之间的边界，以伊明格洋流的形式存在。该研究将探索沿ENE/E格陵兰大陆架和横跨丹麦海峡的源-汇模型，利用沉积物特征记录丹麦海峡两侧和东北格陵兰大陆架的一系列精确年代的高分辨率岩心中成分的时空变化。这些信息将用于推断通过丹麦海峡的海冰运输的变化。考虑到对北极海冰特征变化的持续观测、进入格陵兰-挪威海和北大西洋的海冰通量的变化以及格陵兰冰盖因冰山崩解而可能加速的冰损失，更好地了解这些过程在过去是如何变化的，将有助于预测未来的气候变化。这个项目将开发有助于这种理解的数据集。

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.