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

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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.