Mesoscale Forcing on Ocean Waves During Gulf Stream North Wall Events
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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Under meteorological conditions associated with extreme cold air outbreaks CAO off the U.S. East Coast, rapid growth of large ocean waves sometimes develop along the North Wall of the Gulf Stream. These wave events produce wave heights above those expected given the short fetch and moderate winds. The highest waves are often very localized, which suggests localized forcing by the atmosphere. In this study, results from three cases are examined to characterize the role of high-resolution mesoscale wind forcing in generating localized regions of rapid ocean wave growth during events with large air-sea temperature differences. Analysis of 4 buoys, located in the western Atlantic and coastal waters of North Carolina, were compared to 48 hour atmosphere and ocean model simulations. The Navys, Coupled Oceanographic and Atmospheric Mesoscale Prediction System COAMPS and National Oceanic and Atmosphere Administrations, Wavewatch Three WW3, were used for atmospheric and ocean wave simulations respectively with additional observations from land based stations and ship reports utilized to established model simulation validity. Results of these cases show how mesoscale atmospheric forcing effects rapid growth of ocean waves during CAO and the importance of mesoscale atmospheric modeling in localized generation of ocean wind waves. Additionally, near-shore uniformed observed wind fields were used to generate simulated wave fields then compared to WW3 model output for these cases to further reinforce the rapid and highly non-linear wave growth under strong mesoscale atmospheric forcing during wind wave events in fetch limited environments.
- Physical and Dynamic Oceanography