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Trains of large Kelvin‐Helmholtz billows observed in the Kuroshio above a seamount
Author(s) -
Chang MingHuei,
Jheng SinYa,
Lien RenChieh
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl069462
Subject(s) - seamount , turbulence , geology , buoyancy , dissipation , oceanography , kinetic energy , neutral buoyancy , mode water , atmospheric sciences , physics , meteorology , mechanics , ocean gyre , subtropics , thermodynamics , quantum mechanics , fishery , biology
Trains of large Kelvin‐Helmholtz (KH) billows within the Kuroshio current at ~230 m depth off southeastern Taiwan and above a seamount were observed by shipboard instruments. The trains of large KH billows were present in a strong shear band along the 0.55 m s −1 isotach within the Kuroshio core; they are presumably produced by flow interactions with the rapidly changing topography. Each individual billow, resembling a cat's eye, had a horizontal length scale of 200 m, a vertical scale of 100 m, and a timescale of 7 min, near the local buoyancy frequency. Overturns were observed frequently in the billow cores and the upper eyelids. The turbulent kinetic energy dissipation rates estimated using the Thorpe scale had an average value of O(10 −4 ) W kg −1 and a maximum value of O(10 −3 ) W kg −1 . The turbulence mixing induced by the KH billows may exchange Kuroshio water with the surrounding water masses.