Collaborative Study of Ice-Ocean Interaction in Svalbard

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The small-scale physics of sea ice formation will be studied in a natural setting with the objective to resolve critical paradoxes about the rate of ice formation, supercooling in the ocean boundary layer, and the effective diffusivities of heat and salt. Factors affecting the mass and energy balance of sea ice are currently of much interest both because of the potential impact of sea ice on climate change, and because there is a growing body of evidence that rapid changes are occurring in the Arctic. An important facet of the problem is the exchange of heat and salt at the ice-ocean interface. Here there is a significant gap between theory and observation. Current theory suggests the boundary layer under growing ice should be constrained by double diffusive processes at the ice-ocean interface to force supercooling and in situ frazil ice formation in the boundary layer. Theory also suggests that ocean heat flux will be greater under thin ice than thick ice. These results greatly affect models for small scales and very large scales. Yet, observations indicate these things do not happen. This may be because the existing boundary layer theories do not properly represent the microphysics of the ice formation process. This effort will cooperate with Norwegian colleagues in a combined observational and theoretical investigation to test the hypotheses. The observational work will be done from fast ice in frozen but tidally active fjords in Svalbard. With proper planning and preparation, and the ability to operate from an extensive existing logistics base, the fjord setting will offer a superb natural laboratory for investigating small-scale ice-ocean interaction. This work will take advantage of the recently signed Statement of Cooperation (SOC) between NSF-OPP and the Norsk Polar Institute, and it exemplifies close interaction between U.S. and Norwegian scientists. We will make educational outreach an important part of this project by: supporting a U.S. graduate student who will attend University Courses on Svalbard (UNIS), working with the UNIS students in the field, and giving lectures at UNIS.