A framework for testing global non-hydrostatic models



With the emergence of non-hydrostatic global dynamical cores, an alternative testing strategy is proposed, where the planetary radius is suitably reduced to capture non-hydrostatic phenomena without incurring the computational cost of actual simulations of weather and climate at non-hydrostatic resolution. The procedure is simple and tests various aspects of the discretized hydrostatic and non-hydrostatic equations in the same setting on a sphere. Furthermore, it facilitates verification against Cartesian-domain analytic solutions and against large-eddy simulation (LES) benchmarks available for limited-area models. The proposed framework is illustrated with examples of inertia–gravity wave dynamics in linear and nonlinear regimes, including flows past idealized mountains, stratified shear flows and critical layers. Finally, an intercomparison of the Held–Suarez climate variability for reduced-size planets is presented, which provides a path for future investigations on the dynamics of convective boundary layers on a sphere. This assesses the ability to adequately capture interactions of large-scale dynamics with intermittent turbulent structures, an important aspect of future weather and climate predictions. Copyright © 2009 Royal Meteorological Society