Aspects of the dynamical core of a nonhydrostatic, deep-atmosphere, unified weather and climate-prediction model

The dynamical core, which governs the evolution of resolved fluid-dynamical processes, is a critical element of any atmospheric model. Its governing equations must include all relevant dynamical terms, and the numerical formulae used to approximate them must be accurate, stable and efficient. This is particularly so in a unified modeling environment in which the same dynamical core is used for both operational weather prediction and long term climate simulations. research at the Met Office on unified dynamical core issues is reviewed. Aspects covered include: properties of various equation sets; vertical coordinates; semi-Lagrangian advection and conservation; trajectory computation and dynamical equivalence; horizontal and vertical discretization; and coupling of physical parameterizations to a dynamical core.