Water-ice heat exchange and ice-water boundary layer in freshwater lakes

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The ongoing project is focused on quantification of physical processes, which determine formation and melting of seasonal ice cover. The project is a German-Russian collaborative effort, which combines research on European Arctic lakes and on Lake Baikal. At the initial stage of the project, analysis of results from massive field campaigns revealed the crucial role played by under-ice water motions---geostrophic currents and short-term seiche oscillations---in acceleration of melting at the ice base. These results led to formulation of a unifying hypothesis on scaling the water-ice heat flux with the dissipation rate of the kinetic energy of turbulence. In order to test the hypothesis, a long-term field experiment is proposed based on installation of two identical custom monitoring stations simultaneously in Lake Baikal and in arctic Lake Kilpisjärvi for the entire winter period in both lakes. Performing of such an experiment and analysis of its results requires a 12-month extension of the project. The outcomes of the experiment will provide detailed information on the ice boundary layer dynamics under different mechanisms of turbulence generation. If proven valid, the proposed scaling will allow quantifying the ice-water heat exchange in a wide range of conditions, and can be directly applied for modeling the ice-water boundary layer in polar oceanography and limnology of ice-covered lakes.