The use of commercial CFD-programs for calculating the flow field in the atmospheric boundary layer has been applied for applications in the building construction field for more than a decay. The models can also be used for increasing the understanding of the meteorological dynamics in different kinds of terrain.

Since this kind of models can have a horizontal grid resolution from the order of meters to 100 of meters it is suitable for detailed comparison with field measurements since the grid resolution can resolve local phenomena's that has been observed in the measurements.

Model calculations performed at SMHI with a CFD-model for an area with heterogeneous terrain have been compared with turbulence measurements performed in the area in a 10-meter high tower. The results from the model and the data from the measurements agree very well. The figure below shows a comparison of the turbulent kinetic energy as a function of wind speed between the model and measurements.

In this kind of simulations since the scale of the grid is rather small the quality of the input data has to be high. Both the descriptions of the surface and topography has to be as close to the truth as possible, since the scale is rather small an error of land use would give a wrong surface friction which will result in another flow profile.

Further work planned is to use the model to generate a database that can be used for validation of parameterisation schemes for large scale model i.e. climate models.