Physics-Based Preconditioners for Ocean Simulation

Christopher K. Newman, Dana A. Knoll, T-3 Physics-based preconditioning is a highly successful approach for multiple-time-scale problems where an accurate simulation is desired on the dynamical time scale. In our research we are developing physics-based preconditioners for ocean simulation based on barotropic-baroclinic splitting. Our approach is a fully implicit, fully coupled time integration of the momentum and continuity equations of ocean dynamics, thus reducing the error and increasing the stability of traditional operator splitting. The nonlinear system is solved via preconditioned Jacobian-free Newton-Krylov, where we reformulate traditional barotropic-baroclinic splitting as a preconditioner. Thus the desired solution is time step converged with time steps on the order of the dynamical time scale, a crucial feature as we scale to exascale simulation.