Nonlinear interactions between fluid flows inside and outside of sea ice

Arctic sea ice influences the Earth’s radiation budget through its relatively large albedo, and thus plays an important role in the Earth’s climate system. Hence, predicting changes in the ice cover is crucial to the study of Earth’s climate. The ice-ocean interactions have a controlling effect on the evolution of the ice cover, and the proposed project aims to study these. Specifically, the project will be focussed on the coupling between fluid flows inside and outside of sea ice, which is a reactive porous medium (mushy layer). This coupling controls the transport of salt and heat to the mush-liquid interface, which plays a crucial role in the growth of sea ice. The dynamics of sea ice, and mushy layers generally, forced by an exterior flow remains an open problem in fundamental fluid mechanics. It presents a rich mathematical system to explore, with significant implications for understanding a key aspect of the climate system. The proposal of this project is to develop new analytical and numerical methods to address this problem.

The project will use a combination of direct numerical simulations and mathematical theory to gain an in-depth understanding of these nonlinear interactions and then use this to develop simplified mathematical models for these transport processes. A combination of Lattice Boltzmann and enthalpy methods will be used to simulate the flows. (See figures 1 & 2 for a simulation of fluid flow over pure ice using these numerical techniques.) Furthermore, the mathematical models developed as a part of this project will have an impact on the representation of these processes in the large-scale climate models.