Sensitivity of simulated winds upstream of mountains to horizontal resolution

A severe windstorm in the complex terrain of NW-Iceland on 1-2 February 2002 has been simulated. The windstorm is characterized by large horizontal variability in wind speed and vertically propagating gravity waves that break below 500 hPa. Mesoscale phenomena such as downslope windstorms are generally well simulated but winds immediately upstream of steep mountains are however relatively poorly reproduced. Here, the windstorm is simulated with horizontal resolution up to 330 m and the simulated wind speed upstream of a mountain is compared to observations. The greater the resolution is, the steeper is the topography and the simulated winds are closer to observed winds. At a horizontal resolution of 330 m, the simulated winds are however still stronger than the observed winds.