Numerical Simulation Of Wind Field Over ComplexTerrain

Abstract

The need to know the three dimensional (3D) wind field over a complex terrain as well as the absence of sufficient meteorological information lead to an increase of the use of numerical tools for the wind field simulation. The main purpose of this work is the evaluation of the results and performance of two mesometeorological models. One is a diagnostic model, NUATMOS, and the other is a prognostic, MEMO. Both solve their numerical equations in terrain-following'' coordinates and variable vertical grid spacing NUATMOS produces a 3D mass consistent wind field based on observations arbitrarily located. This wind field satisfies the equation of continuity. The possibility of incorporating the atmospheric stability is done trough the input parameter a (which is related with the Froude number). MEMO is a non-hydrostatic model that solves numerically the conservation equations for mass, momentum and scalar quantities like energy, humidity or pollutant concentration, using as turbulent parameterizations the K-e theory. These models were applied at two regions of complex terrain in the central part of Portugal, named Aveiro and Poiares. The application of NUATMOS to Aveiro's region included a sensitivity analysis, for some of the input parameters. Comparison between the results of the models and real meteorological data allowed the acquaintance of the performance of the two models. On both, results were very encouraging. Nevertheless, NUATMOS, due to its simplicity, should be used on applications that need short time results. On the other hand, MEMO should be used on situations that requires more deep studies, and a more detailed knowledge of the wind field features.