Modeling of mountain waves over the Pyrenees

When stably stratified air flows over a topographic obstacle with a vector component perpendicular to the topographic barrier, gravity waves (or mountain waves) may be generated above or downwind of the mountain. These waves can propagate energy vertically or disperse it horizontally. Vertically-propagating waves with sufficient amplitude may break in the troposphere or lower stratosphere, and this breaking may result in severe to extreme turbulence within the wave-breaking region and nearby. There is also a strong coupling between the structure and evolution of the waves, the rotors that may be associated with them and the atmospheric boundary layer.

In this work, an observational case where mountain waves were developed over the Pyrenees is analyzed. We use the mesoscale numerical model Weather Research and Forecasting (WRF) to examine the meteorological processes that are important in the episode.