Development of an atmospheric climate model with self-adapting grid and physics

Abstract

An adaptive grid dynamical core for a global atmospheric climate model has been developed. Adaptations allow a smooth transition from hydrostatic to non-hydrostatic physics at small resolution. The adaptations use a parallel program library for block-wise adaptive grids on the sphere. This library also supports the use of a reduced grid with coarser resolution in the longitudinal direction as the poles are approached. This permits the use of a longer time step since the CFL number restriction (CFL < 1) in a regular longitude-latitude grid is most severe in the zonal direction at high latitudes. Several tests show that our modelling procedures are stable and accurate.