THE INFLUENCE OF STATIC STABILITY ON THE EFFECTIVE ROUGHNESS LENGTHS FOR MOMENTUM AND HEAT-TRANSFER

The area-averaged properties of the planetary boundary layer over heterogeneous terrain are considered. Previous studies which dealt with the average momentum transfer properties in neutral static stability conditions are extended to include the influence of stratification and also area-averaged properties for heat transfer. Results from numerical simulations demonstrate the utility of values of effective roughness length for both momentum and heat transfer. A heuristic model is found to show good agreement with the numerical simulations and to provide a simple method for estimating these roughness lengths for use in boundary-layer parametrization.