Collaborative Proposal: Joint US/Norwegian Studies of Ice/Ocean Interaction in Frozen Fjords

智力优势：本研究与挪威和其他美国科学家合作，将现代海洋学设备以新颖的方式组合在一起，在冰/海洋界面附近相对受控的冰覆盖峡湾潮汐流环境中测量动量、热量和盐的湍流通量。它建立在一个充分记录的类似测量的基础上，这在海洋学中是罕见的，利用这些数据来解决海洋边界层湍流运输的基本问题。该项目的第一阶段通过观测证明，当海冰冻结与融化时，冰/海洋界面的热量和盐的双重扩散是根本不同的，因为晶体生长的方式缓解了非常靠近界面的过冷倾向（和潜在的冰的产生）。它还导致了假底形成和迁移理论的发展，该理论表明融化过程中的双重扩散过程对浮冰的总能量平衡的重要性。为了扩大合作，观测和模拟工作将用于(1)量化冰海边界的热盐交换系数；(2)研究表面粗糙度和近表面盐度水平变化对湍流交换的影响；(3)了解沿海潜热多裂谷形成的盐水增强海水的形成和下坡流动。更广泛的影响：这项工作的协作性质及其与斯瓦尔巴群岛大学课程（UNIS）的密切联系，在许多方面都是有益的。在一系列描述最新研究的高要求讲座中，学生们将被介绍极地空气-海冰相互作用的概念，然后观察并直接参与在极地条件下部署和监测最先进的仪器。这是双向的。通过这门课程，首席研究员接触了来自法国、德国、英国、波兰、日本和俄罗斯等多个国家的聪明、上进心强的学生（男女比例大致相等）。来自UNIS课程和合作工作的几名学生继续对极地海洋学和海冰研究感兴趣，并且都在攻读博士学位。这项工作的美国和挪威合作者都很清楚，人们对极地地区（特别是海冰和稠密水的形成）对全球气候的反应和影响都非常感兴趣。可以毫不夸张地说，我们都有一种紧迫感，那就是扩大我们对空气-海冰相互作用基本原理的理解，以便用来预测未来变化的大尺度模型能结合最好的物理学。

ABSTRACTMcPheeOPP-0324043Intellectual Merit: This research brings to bear modern oceanographic equipment combined in novel ways to measure turbulent fluxes of momentum, heat, and salt near the ice/ocean interface in the relatively controlled environment of ice-covered fjords with tidal flow, in collaboration with Norwegian and other American scientists. It builds on a well-documented record of making similar measurements, which are rare in oceanography, using the data to address fundamental issues of turbulent transport in ocean boundary layers. The first phase of the project demonstrated observationally that double-diffusion of heat and salt at the ice/ocean interface is fundamentally different when sea ice is freezing compared with melting, because of the way crystal growth relieves supercooling tendency (and potential frazil ice production) very near the interface. It also led to development of a theory of false bottom formation and migration that suggests the importance of the double diffusive process during melting to the overall energy balance of pack ice. In extending the collaboration, observational and modeling work will be used to (1) quantify the exchange coefficicents for heat and salt at the ice ocean boundary; (2) investigate the impact of horizontal changes in surface roughness and near surface salinity on turbulent exchange; and (3) understand the formation and downslope flow of brine-enhanced seawater formed in coastal, latent heat polynyas.Broader Impact: The collaborative nature of this work, and its close connection with the University Courses on Svalbard (UNIS), has been beneficial in a number of ways. The students are introduced to the concepts of polar air-sea-ice interaction during a demanding lecture series describing the latest research, and then observe and participate directly in deploying and monitoring state-of-the-art instrumentation under polar conditions. It works both ways. Through the course the Principal Investigator has had contact with bright, highly motivated students (about equally divided among men and women) from a number of countries including (besides Scandinavia) France, Germany, Great Britain, Poland, Japan, and Russia. Several students from the UNIS course and collaborative work have continued their interest in polar oceanographic and sea-ice research, and are all pursuing advanced degrees at the doctoral level. The American and Norwegian collaborators in this work are well aware of general heightened interest in both the response and impact of polar regions (particularly sea ice and dense water formation) on global climate. It is probably not an overstatement to say that we share a sense of urgency in broadening our understanding of the fundamentals of air-sea-ice interaction, so that the large scale models used to predict future change incorporate the best physics.