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 (C) 2009 Royal Meteorological Society