Collaborative Research: Elucidating the Ocean Dynamics Governing Melt at Glaciers Using Lagrangian Floats

这项拟议中的研究将确定导致阿拉斯加冰川融化的物理过程，该冰川终止于峡湾。这项研究将试图证明，与冰川融化相关的水流相比，海平面以下的循环细胞和波浪是否会导致更强的速度。该项目将开发三维漂移的仪器，能够沿着固定深度漂移或随水类型移动。这些漂流仪器将与固定在一个地方的仪器和船舶测量相结合，并与计算机模型相结合，以破译冰川表面不同三维运动的相互作用;并解决流动的时间和空间结构，增加了冰川的热通量和融化。了解这些过程将有助于预测冰川质量损失和由此产生的融水流入极地海洋的情况。作为更广泛的影响，这项研究将有助于在全球范围内制定海底冰川融化。主要研究者是一名早期职业研究者，以及两名Co-PI。该项目将支持几个研究生。拟议的工作将描述驱动近冰川循环和阿拉斯加勒孔特冰川海底冰川融化的过程。这一假设是，冰川融化的加速是由冰川表面不同尺度的再循环和内波造成的，而这些再循环和内波运动并不包括在冰川融化的标准海洋模型参数化中;而且这些再循环和内波运动压倒了羽流速度。该假设将通过开发三维漂移的微浮子（µ浮子）进行测试，微浮子能够沿着固定深度漂移或随水移动（等密度表面）。该研究将使用声学跟踪拉格朗日微浮子，系泊和船舶观测以及数值模拟来阐明以下因素的相互作用：（1）排放羽流驱动的夹带和再循环;（2）内部波及其对冰川表面垂直速度的贡献;以及（3）被认为增强冰川热通量的横向环流的时空结构。这些过程将有助于预测冰川质量损失和由此产生的融水流入极地海洋的情况。高分辨率数值模拟将为部署提供信息，并用于综合结果。作为更广泛的影响，这项研究将为海底融化的参数化提供信息。PI和两名Co-PI是早期职业调查员，该项目将支持几名研究生。该奖项反映了NSF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 proposed study will determine the physical processes that cause melting at an Alaskan glacier that ends in a fjord. The study will try to prove whether recirculating cells and waves below the sea-surface cause stronger velocities than the flows associated with melting glaciers. The project will develop instruments that drift in three dimensions, capable of drifting along a fixed depth or move with a water type. These drifting instruments will be combined with instrumentation that is fixed at one place and with ship measurements, and with computer models to decipher the interactions of different three-dimensional motions at the glacier face; and to resolve the time and space structure of flows that enhance heat flux to, and melting of, the glacier. Understanding of these processes shall allow projections of glacier mass loss and resulting melt-water flux into the polar oceans. As Broader Impacts, the study will help in global-scale formulations of submarine glacial melting. The Principal Investigator is an early career investigator, as well as two of the Co-PIs. The project will support a couple of graduate students.The proposed work will characterize the processes that drive near-glacier circulation and submarine glacial melt at LeConte Glacier, Alaska. The hypothesis is that accelerated glacier melting results from different-scale recirculations and internal waves at the glacier face that are not included in standard ocean-model parameterizations of glacial melt; and that these recirculations and internal wave motions overwhelm the plume velocities. The hypothesis will be tested via development of microfloats (µfloats) that drift in 3D, capable of drifting along a fixed depth or move with water (an isopycnal surface). The study will use acoustically tracked Lagrangian µfloats, mooring and vessel observations, and numerical modeling to elucidate the interplay of: (1) entrainment and recirculation driven by discharge plumes; (2) internal waves and their contributions to vertical velocity at the glacier face; and (3) the spatiotemporal structure of lateral circulations believed to enhance heat flux to the glacier. These processes shall allow projections of glacier mass loss and resulting melt-water flux into the polar oceans. High-resolution numerical simulations will inform deployments and be used to synthesize results. As Broader Impacts, the study will inform parametrizations of submarine melting. The PI and two Co-PIs are early career investigators, and the project will support a couple of graduate students.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.