Evolution of Glacial Meltwater in the North Atlantic Current - Subpolar Front System

上一个冰河时期大冰原的融化导致全球海平面上升了约130米。在这个项目中，将开发一个计算机模型来模拟冰川水从劳伦泰德冰原流入北大西洋的路径。劳伦泰德冰原是上一个冰河时期覆盖北美北部的大冰原。该项目将包括对小规模漩涡及其对冰川水运动的影响进行建模，这将有助于了解海洋对冰盖变化的反应。这些结果对于理解今天从其他冰原（如格陵兰冰原）释放的冰川水的作用非常重要。该项目将支持一名研究生和三名本科生，并将制作一本操作手册，以便科学家可以在其他项目中使用或调整该模型。将发展一个代表海洋环流和海冰并解决海洋中尺度涡旋的数值模式，以产生北大西洋流-次极锋系统中冰川水演变的详细模拟。重点将放在沿拉布拉多大陆架不同位置的劳伦泰德冰盖的冰川融水上，那里存在冰流向亚极地环流输送物质的证据，并通过弗拉姆海峡，这将允许代表来自北冰洋，特别是麦肯齐河的融水来源。将解决两个问题：(1)在流向北大西洋北部深水形成区时，冰川水的温度和盐度在多大程度上发生了改变？(2)哪个过程（涡流引起的混合或海气相互作用）最有效地改变了流向这些地区的冰川水的性质？解决这些问题的工作计划有三个方面。首先，将配置一个耦合的海洋环流-海冰模式来代表北大西洋的亚极地。其次，耦合模式将通过使用来自海洋巡航、水文气候学和卫星任务的现代观测结果进行检验。最后，利用耦合模型进行实验分析，量化冰川水在向深水形成区迁移过程中的侵蚀特性，并评价不同侵蚀因子的作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The melting of the great ice sheets of the last Ice Age caused sea level to rise by about 130 m globally. In this project a computer model will be developed to simulate the pathways of glacial water introduced into the North Atlantic Ocean from the Laurentide Ice Sheet – the great ice sheet that covered northern North America during the last Ice Age. The project will include modeling of small-scale eddies and their influence on glacial water movements which will help in the understanding of the ocean’s response to ice sheet changes. The results will be important for understanding the role of glacial waters released today from other ice sheets such as the Greenland Ice Sheet. The project will support a graduate student and three undergraduate students, and a how-to manual will be produced so that scientists can use or adapt the model for other projects.A numerical model which represents ocean circulation and sea ice and which resolves ocean mesoscale eddies will be developed to produce detailed simulations of the evolution of glacial water in the North Atlantic Current-Subpolar Front system. Focus will be on glacial meltwater which emanated from the Laurentide Ice Sheet at different locations along the Labrador Shelf, where evidence for ice streams delivering material into the sub-polar gyre exists, and through Fram Strait, which will allow representation of a source of meltwater from the Arctic Ocean, and in particular the Mackenzie River. Two questions will be addressed: (1) To which extent are the temperature and salinity of glacial waters modified as they flow towards deep-water formation areas in the northern North Atlantic? (2) Which processes (eddy-induced mixing or air-sea interactions) most effectively modify the properties of glacial waters en route to these areas? The work plan to address these questions is threefold. First, a coupled ocean circulation-sea-ice model will be configured to represent the subpolar North Atlantic. Second, the coupled model will be tested by using modern observations from oceanographic cruises, hydrographic climatologies, and satellite missions. Finally, experiments with the coupled model will be conducted and analyzed to quantify the erosion of glacial water properties en route to deep-water formation regions and evaluate the role of different eroding factors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.