Oceans at MIT

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20171105T020000 -0400 -0500 20181104T020000 EST 20180311T020000 -0500 -0400 EDT vuc1onajs0fpct9nl84jltm95g@google.com 20180503T092242Z MIT Seminar | PAOC Oceanography and Climate Sack Lunch Despite the major role played by mesoscale eddies in redistributing the energy of the large-scale circulation, our understanding of their dissipation is still incomplete. This study investigates the generation of internal waves by decaying eddies in the North Atlantic western boundary. The eddy presence and decay are measured from the altimetric surface relative vorticity associated with an array of full-depth current meters extending ~100 km offshore at 26.5N. In addition, internal waves are analysed over a topographic rise from 2-year high-frequency measurements of an Acoustic Doppler Current Profiler (ADCP), which is located 13 km offshore in 600 m deep water. Despite an apparent polarity independence of the eddy decay observed from altimetric data, the flow in the deepest 100 m is enhanced for anticyclones (25.2 cm/s) compared with cyclones (-4.7 cm/s). Accordingly, the internal wave field is sensitive to this polarity-dependent deep velocity. This is apparent from the eddy-modulated enhanced dissipation rate, which is obtained from a finescale parameterization and exceeds 10^-9 W/kg for near-bottom flows greater than 8 cm/s. The present study underlines the importance of oceanic western boundaries for removing the energy of low-mode westward-propagating eddies to higher-mode internal waves. 20160330T120000 20160330T130000 54-915 0

SLS-LOUIS CLEMENT (LDEO) – Generation of internal waves by eddies impinging on the western boundary of the North Atlantic