The subgrid problem of thermal convection in the Earth's liquid core

The problem of turbulent thermal convection in the Earth's liquid core is considered. Following assumptions on decreasing of the spatial scales due to rapid rotation, we propose a subgrid model of eddy diffusivity used in the large-scale model. This approach makes it possible to model realistic regimes with small Ekman and Rossby numbers and with a sufficiently large Rayleigh number. An estimate obtained for the averaged kinetic energy is comparable with observations. The model includes rotation of the solid core due to viscous torque.