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

A general circulation model using a full-Galerkin method is developed for t he simulation of atmospheric climate and variability. Two variants of the G alerkin method, the spectral-transform method and the finite-element method , are used in this model for the horizontal and vertical representation, re spectively. The baroclinic dynamics of this model are examined by performin g linear normal mode and nonlinear lifecycle calculations of baroclinic wav es. The results suggest that the finite-element method resolves the vertica l structure of the baroclinic normal mode better than the finite-difference method. The generation, propagation, and decay of baroclinic waves are wel l simulated in this model. A long-term integration was carried out with a z onally symmetric forcing applied to the GCM. The simulated climate with a f lat topography and that produced in the model hemisphere with an idealized mountain are compared. The results suggest that the presence of mountain do es not alter the meridional structure of the zonal mean circulation. Compar isons of these time-mean statistics to observed winter time statistics in t he real atmosphere indicate that this GCM produces a reasonable general cir culation of the atmosphere. (C) 2000 Published by Elsevier Science B.V. on behalf of IMACS.