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

知识价值：这项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结合起来，在相对受控的冰盖峡湾潮汐流动环境中测量冰/海洋界面附近动量、热量和盐的湍流通量。它建立在一个有据可查的记录，使类似的测量，这是罕见的海洋学，使用的数据来解决海洋边界层湍流传输的基本问题。该项目的第一阶段在观测上表明，当海冰冻结与融化时，冰/海洋界面处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接近界面的过冷趋势（和潜在的冰生成）。它还导致了假底形成和迁移理论的发展，该理论表明了融化过程中的双重扩散过程对浮冰整体能量平衡的重要性。在扩大合作的过程中，观测和建模工作将用于（1）量化冰洋边界处的热量和盐份交换系数;（2）调查表面粗糙度和近表面盐度水平变化对湍流交换的影响;（3）了解沿海潜热冰穴形成的盐水增强海水的形成和下坡流动。这项工作的协作性质及其与斯瓦尔巴特群岛大学课程的密切联系在许多方面都是有益的。学生们在描述最新研究的一系列苛刻的讲座中介绍了极地空气-海冰相互作用的概念，然后观察并直接参与极地条件下部署和监测最先进的仪器。它是双向的。通过该课程，主要研究者与来自许多国家的聪明、积极性高的学生（男女比例大致相等）进行了接触，这些国家包括（除斯堪的纳维亚半岛外）法国、德国、英国、波兰、日本和俄罗斯。来自联合国新闻处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，并都在攻读博士一级的高级学位。这项工作的美国和挪威合作者非常清楚，人们对极地地区（特别是海冰和密集水的形成）对全球气候的反应和影响普遍感到兴趣。可以毫不夸张地说，我们都有一种紧迫感，那就是扩大我们对气-海-冰相互作用基本原理的理解，以便用于预测未来变化的大尺度模型包含最好的物理学。

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.