Influence of the wind drag coefficient in storm surge models

In hydrodynamic simulations the wind drag coefficient represents the effects of the sea surface roughness. It is closely related to the local wave field which is not always fully determined by the local wind. Accurate model-predictions of storm surge water levels along the coast remain difficult, and this is mainly associated with uncertainties regarding the variation of wind drag coefficients at high wind velocities. Wind drag formulations that are only a function of the wind, might therefore lead to inaccurate predictions of surge models.

Relation between wind drag coefficient and wind speed

Relation between wind drag coefficient and wind speed. © G. Bruss, FTZ.