Air-Sea Interaction and the Spatial Variability of the Surface Evaporation Duct in a Coastal Environment

Aircraft observations are presented of the horizontal variability in the depth of the surface evaporation duct and the relationship with the mesoscale structure of air-sea interaction processes. The 2-dimensional fields of near-surface wind, stress, wind-stress curl, air and sea-surface temperature are measured directly for flow around a headland. The sea surface temperature field indicates cold upwelling driven by the windstress curl. Boundary-layer stability responds rapidly to the spatial changes in surface temperature. These changes result in modification of the evaporation duct, which decreases significantly in depth over the cooler upwelling water.