Comparison of Mean Wind Speeds and Turbulence at a Coastal Site and Offshore Location

Abstract

Observations of mean wind speed and longitudinal turbulence at a height of 8 m over the Atlantic ocean, 5 km off Long Island, New York, were compared with simultaneous observations at the beach. Results were grouped into wind direction classes characteristic of changes in roughness and fetch. Mean winds over the ocean were 15?100% higher than those at the beach. Changes in turbulence seem to depend on variations in the aerodynamic roughness of the sea surface and the thermal processes that take place over the water. A decrease in turbulence over the ocean relative to that at the beach due to a decrease in sea surface roughness for alongshore flows could be predicted reasonably well with a simple logarithmic wind profile relationship.