Topographic Vorticity-Mode Mesoscale-β (TVM) Model. Part I: Formulation

The three-dimensional, flat-terrain, finite-difference URBMET vorticity, mode mesoscale-beta model has been modified to include topographic effects. The resulting topographic vorticity-mode mesoscale-beta (TVM) model is hydrostatic, Boussinesq, and incompressible. The prognostic turbulent kinetic energy equation has been improved, and use of an implicit vertical diffusion scheme has increased the minimum allowable time step of integration. Part I of this paper presents the details of the TVM formulation, boundary conditions, and numerics. Part II presents comparisons between simulated and observed values for a test period from the Fos observational campaign, during which data were obtained in a complex-terrain coastal area in the south of France.