Heinrich Event Iceberg Flux, Melting, and Ocean Circulation in the North Atlantic

该项目的总体目标是生成关于北大西洋一套深海沉积物岩心的高分辨率数据，并将其结果与主要冰山排放的阶段性生成的概念模型和计算机模型进行比较。 研究人员的目标是产生一个空间系统的冰筏碎片（IRD）的浓度，来源和通量的数据集，这些碎片来自北美劳伦泰德冰盖（LIS），分布在从西向东延伸到亚极地海洋的一系列地点，以及南到亚热带地区。 这些数据将被用来检验与最后一次冰期的海因里希事件有关的冰山融化的成因和随后的分布假设，并提供对冰冻圈和海洋环流相互作用的见解。灾难性的冰山放电（海因里希）事件是地球冰冻圈，海洋和气候之间最大的已知相互作用。尽管关于其原因和后果仍有争议，但至少在一部分事件中，证据与它们对副极地大西洋的盐度和稳定性的可能影响是一致的，大西洋纬向翻转环流（AMOC）显着减弱，北方半球变冷，南半球变暖，以及全球水文循环和大规模大气环流和组成的变化。 然而，与最后一次冰期期间最初确定的六个事件中的两个事件有关的沉积物在东亚极地北大西洋具有非常不同的沉积特征，在那里它们最常被比较。这对任何单一的机制提出了一个问题来解释这些事件，需要对不同的事件进行例外或对比解释。更广泛的影响涉及促进对冰冻圈，海洋和气候系统的理解。 该项目将支持一名早期职业博士后研究员和几名本科生参与研究。研究参与者将参加一次研究巡航，以恢复新的沉积物，这是一项合作努力的一部分，该努力与国际努力的目标相一致，以了解耦合的北南极-北极系统。“更广泛的影响”还包括通过与纽约市公立高中教师和学生合作进行外联。该项目的成员将参加两年一度的拉蒙特-多尔蒂地球观测站开放日，该活动吸引了数千名各年龄段的游客来到校园。

This project generally aims to generate high-resolution data on a suite of deep-sea sediment cores from the North Atlantic Ocean and to conduct a comparison of the results with conceptual and computer models for the episodic production of major iceberg discharges. The researchers aim to produce a spatially systematic dataset of the concentration, provenance and flux of ice-rafted debris (IRD), derived from the North American Laurentide Ice Sheet (LIS) in an array of sites extending from west to east across the subpolar ocean, and south to the subtropics. These data will be used to test hypotheses regarding the genesis and subsequent distribution of melting icebergs associated with the Heinrich events of the last glaciation and to provide insights into the interactions of cryosphere and ocean circulation.The catastrophic iceberg discharge (Heinrich) events that punctuated the last ice age were among the largest known interactions of the Earth's cryosphere, ocean, and climate. Although there is continued debate about their causes and consequences, in at least a subset of the events, the evidence is consistent with their likely influence on the salinity and stability of the subpolar Atlantic, significant weakening of the Atlantic meridional overturning circulation (AMOC), cooling of the northern hemisphere, warming of the southern hemisphere, and shifts in the global hydrological cycle and large-scale atmospheric circulation and composition. Yet deposits associated with two of the six events originally identified during the last glaciation have very different sedimentary characteristics in the eastern subpolar North Atlantic, where they have most commonly been compared. This poses a problem for any single mechanism proposed to explain the events, requiring exceptions or contrasting explanations for different events.The Broader Impacts involve advancing understanding of the cryosphere, ocean, and climate system. The project will support an early career postdoctoral researcher and several undergraduates in the research. Research participants will take part in a research cruise to recover new sediments as part of a collaborative effort that is aligned with the goals of international efforts to understand the Coupled North Atlantic-Arctic System. The Broader Impacts also involve outreach through collaboration with for New York City public high school teachers and students. Members of the project will participate in the biennial Lamont-Doherty Earth Observatory Open House which draws thousands of visitors of all ages to the campus.