High‐frequency internal waves and thick bottom mixed layers observed by gliders in the Gulf Stream

Abstract Autonomous underwater gliders are conducting high‐resolution surveys within the Gulf Stream along the U.S. East Coast. Glider surveys reveal two mechanisms by which energy is extracted from the Gulf Stream as it flows over the Blake Plateau, a portion of the outer continental shelf between...

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Bibliographic Details
Published inGeophysical research letters Vol. 44; no. 12; pp. 6316 - 6325
Main Author Todd, Robert E.
Format Journal Article
LanguageEnglish
Published Washington John Wiley & Sons, Inc 28.06.2017
Subjects
Banks (topography)
Bathymetry
Brunt-vaisala frequency
Buoyancy
Coastal environments
Continental shelves
Energy
Fluid dynamics
Gliders
Gulf Stream
High resolution
Internal waves
Lee waves
Ocean currents
Outer continental shelf
Physiographic features
Plateaus
Polls & surveys
Rivers
Slope
Stream discharge
Stream flow
Surveys
Topography
Topography (geology)
Turbulence
Underwater gliders
Underwater vehicles
Vertical velocities
North Carolina
Florida
United States > US
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Summary:Abstract Autonomous underwater gliders are conducting high‐resolution surveys within the Gulf Stream along the U.S. East Coast. Glider surveys reveal two mechanisms by which energy is extracted from the Gulf Stream as it flows over the Blake Plateau, a portion of the outer continental shelf between Florida and North Carolina where bottom depths are less than 1000 m. Internal waves with vertical velocities exceeding 0.1 m s −1 and frequencies just below the local buoyancy frequency are routinely found over the Blake Plateau, particularly near the Charleston Bump, a prominent topographic feature. These waves are likely internal lee waves generated by the subinertial Gulf Stream flow over the irregular bathymetry of the outer continental shelf. Bottom mixed layers with O(100) m thickness are also frequently encountered; these thick bottom mixed layers likely form in the lee of topography due to enhanced turbulence generated by O(1) m s −1 near‐bottom flows. Key Points Spray gliders provide high‐resolution surveys of the Gulf Stream along the U.S. East Coast High‐frequency internal lee waves are generated by Gulf Stream flow over Blake Plateau Thick bottom mixed layers are common over Blake Plateau
ISSN:0094-8276
1944-8007
DOI:10.1002/2017GL072580