Wind profile effects on gravity wave drag and their impact on the global atmospheric circulation Supervisors:

The drag force associated with gravity waves generated by flow over the world’s mountain ranges tends to decelerate the large-scale atmospheric circulation, and must be parametrized in global weather prediction and climate models, since it is still not adequately resolved by those models. Such parametrizations have proved to be of crucial importance for improving the skill of weather forecasts. However, existing drag parametrizations are very crude, neglecting, for example, the impact of any wind variations with height on the value of the surface drag, and on the way the momentum flux associated with the waves is affected by so-called critical levels. A considerable imbalance is known to exist in the most recent evaluations of the earth’s angular momentum budget, and it is possible that imperfections in the representation of gravity wave drag are responsible for it.