[1] Recent field and laboratory observations indicate that the variation of drag coefficient with wind speed at high winds is different from that under low-to-moderate winds. By taking the effects of wave development and sea spray into account, a parameterization of sea surface aerodynamic roughness applicable from low to extreme winds is proposed. The corresponding relationship between drag co...

The effects of breaking waves on near-surface wind turbulence and drag coefficient are investigated using large-eddy simulation. The impact of intermittent and transient wave breaking events (over a range of scales) is modeled as localized form drag, which generates airflow separation bubbles downstream. The simulations are performed for very young sea conditions under high winds, comparable to...

Recent observational studies demonstrate that airsea momentum flux at high wind conditions in hurricanes strongly depends on the wave field and that the drag coefficient (Cd = u*/U10) levels off or even decreases at very high winds (Powell et al. 2003). Yet most hurricane research and forecast model utilize the bulk parameterization, i.e., the boundary layer parameterization based on the Monin-...

The questions of how wind and ocean waves interact and how this coupling should be parameterized to optimally derive the surface wind stress remain open and central to estimating air-sea coupling at the global and local scales. While much attention has been given to evaluating the effect of the wind-driven waves upon the surface wind stress and air-sea drag coefficient, less emphasis has been g...

A neutrally stratified turbulent airflow over a very young sea surface at a high-wind condition was investigated using large-eddy simulations. In such a state, the dominant drag at the sea surface occurs over breaking waves, and the relationship between the dominant drag and local instantaneous surface wind is highly stochastic and anisotropic. To model such a relationship, a bottom boundary st...

Pressure differences across topography generate a form drag that opposes the flow in the water column, and viscous and pressure forces acting on roughness elements of the topographic surface generate a frictional drag on the bottom. Form drag and bottom roughness lengths were estimated over the East Flower Garden Bank (EFGB) in the Gulf of Mexico by combining an array of bottom pressure measure...

Inverse models are developed that use data and dynamics to estimate optimally the breaking-wave-driven setup and alongshore current, as well as the cross-shore forcing, alongshore forcing, and drag coefficient. The inverse models accurately reproduce these quantities in a synthetic barred-beach example. The method is applied to one case example each from the Duck94 and SandyDuck field experimen...