A general circulation model of the atmosphere using the full-Galerkin method Original Research Article

A general circulation model using a full-Galerkin method is developed for the simulation of atmospheric climate and variability. Two variants of the Galerkin method, the spectral-transform method and the finite-element method, are used in this model for the horizontal and vertical representation, respectively. The baroclinic dynamics of this model are examined by performing linear normal mode and nonlinear lifecycle calculations of baroclinic waves. The results suggest that the finite-element method resolves the vertical structure of the baroclinic normal mode better than the finite-difference method. The generation, propagation, and decay of baroclinic waves are well simulated in this model. A long-term integration was carried out with a zonally symmetric forcing applied to the GCM. The simulated climate with a flat topography and that produced in the model hemisphere with an idealized mountain are compared. The results suggest that the presence of mountain does not alter the meridional structure of the zonal mean circulation. Comparisons of these time-mean statistics to observed winter time statistics in the real atmosphere indicate that this GCM produces a reasonable general circulation of the atmosphere.