Comments on “A One-Level Mesoscale Model for Diagnosing Surface Winds in Mountainous and Coastal Regions”

Abstract

Mass and Dempsey (1985) have reformulated the equations for the one-level sigma-system model over complex terrain and suggested they have removed the large hydrostatic part of the horizontal pressure-gradient force (PGF). It is shown that although the coefficient of g?σZs was greatly reduced (compared to 1), the complete elimination of the hydrostatic PGF cannot be done unless the surface temperature is redefined as the sum of a perturbation temperature and a basic rest-state temperature. The alternative formula in which the hydrostatic PGF terms were totally removed is presented.