A pore-scale numerical model for simulating sea ice

During melting and growing sea ice dynamically changes its pore-scale transport properties, such as tortuosity and connectivity. This dynamics determines sea ice permeability and the macroscopic transport of nutrients-rich brine to the underlying ocean. We present a lattice-Boltzmann-based model that simulates the microscopic heat and mass transport processes in sea ice and simultaneously tracks the evolution of its pore-scale morphology. The brine-ice initial matrix is reconstructed from 3D X ray tomographic images of sea-ice in thermodynamic equilibrium. Upon imposing an environmental deviation from such an equilibrium, heat and mass transport equations are then solved at the scale of brine pockets, with proper boundary conditions at the pore wall interfaces. A local moving boundary scheme based on brine/ice volume fractions is applied to deal with complex geometrical scenarios. We present results of test cases that allow the computation of the onset of bouyancy-driven brine convection at different sea-ice depths, during melting and growing.