Dynamics of winds over Iceland in a numerical downscaling of current climate

Seventeen years of flow over Iceland is simulated with the WRF numerical system at a horizontal resolution of 3 km. The flow is forced by the ECMWF reanalysis. The simulation reveals very large horizontal variability in mean and maximum winds. There are clear topographic effects, dominated by gravity waves on the downstream slopes of the resolved mountains. There are also clear signals of topographic channeling. Weak mean and extreme winds in certain regions can also be attributed to topographic sheltering. Consequently, the pattern of wind extremes is very sensitive to the wind direction. As expected, surface friction has a clear impact on the mean wind and wind extremes, but there are indications that this frictional effect may be overestimated. This downscaled atmospheric flow forms the basis for estimating the wind energy potential for Iceland and find potential sites for wind mill parks.