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Secondary circulation associated with a shelfbreak front
Author(s) -
Barth John A.,
Bogucki Darek,
Pierce Stephen D.,
Kosro P. Michael
Publication year - 1998
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 - 10.1029/98gl02104
Subject(s) - front (military) , downwelling , upwelling , geology , hydrography , secondary circulation , water mass , submarine pipeline , circulation (fluid dynamics) , oceanography , frontogenesis , ocean current , mesoscale meteorology , mechanics , physics
Evidence for secondary circulation associated with a shelfbreak front is obtained from a high‐resolution, cross‐shelf section of hydrographic, optical and velocity fields. Convergence in the bottom boundary layer on the inshore side of the front and subsequent upwelling into the interior is evident by a mid‐water region of suspended bottom material emanating from the foot of the front and extending to within 35 m of the surface, 80 m above bottom. Downwelling on the offshore side of the front in the upper water column is inferred from a 20‐m downward bend of the subsurface phytoplankton layer. These observations are in agreement with recent model predictions for secondary circulation near an idealized shelfbreak front. Convergence in measured cross‐shelf velocity at the foot of the front is consistent with upwelling of bottom material detected there. An estimate of 9±2 m day −1 of upwelling on the inshore side of the shelfbreak front is obtained, implying a transit time from the bottom to the surface of 10–16 days.