Abstract
This paper describes a one-level, sigma-coordinate, mesoscale model suitable for diagnosing surface winds in mountainous and coastal regions. The model requires only modest computer resources and needs little data for initialization. Energy and momentum conservation equations are integrated under steady, specified synoptic-scale height and temperature fields to a steady state to diagnose surface wind and temperature fields forced by complex terrain. If diabatic forcing is desired, the model uses the steady state results as an initial state from which the model is integrated, with varying diabatic forcing, to the verification time. The model has no mass budget, but under the hydrostatic assumption the mass field (and therefore the surface pressure field) is determined by the vertical temperature structure, which in the model is parameterized in terms of surface temperature.
Four model runs and corresponding observed wind fields are presented. They suggest that the model can diagnose many details of mesoscale flow in complex terrain for a variety of flow directions and diabatic forcings. It is suggested that adiabatic warming and cooling play a crucial role in producing topographic deflection and channeling. Recommendations of possible improvements to the model are given.
