Model and observations of time-dependent upwelling over the mid-shelf and Slope

Journal Article · Mon Dec 01 04:00:00 EST 1980 · J. Phys. Oceanogr.; (United States)

DOI:https://doi.org/10.1175/1520-0485(1980)010<1574:AMAOOT>2.0.CO;2· OSTI ID:7063985

Janowitz, G S; Pietrafesa, L J

A simple model of time-dependent quasi-geostrophic upwelling over an outer continental shelf and slope region is considered with the velocity assumed independent of the alongshore coordinate. The flow is at rest and stably stratified when a uniform alongshore wind stress tau is applied. Initially, the onshore flow in the water column balances the offshore top Ekman volume flux. As time progresses the bottom Ekman layer supplied increasingly more of the required onshore flux and the onshore flow in the interior of the water column decreases. The shallower water spins up first leading to both a coastal jet and an upward bulge in the isopycnal surfaces which propagates offshore with a speed equal to 0.012(tau/p)/sup 1/2/h/sub x/, where h/sub x/ is the local slope. At the shelf break, if h/sub x/xh/h/sub x//sup 2/>2 another upward bulge of the isopycnal surfaces will develop at the onset of upwelling favorable winds and will be of greater amplitude than the propagating bulge. The theory is generalized to include the effects of a time-dependent wind stress and those of a specified time-dependent alongshore pressure gradient. The velocity induced by the deformation of the density field is then calculated. Comparisons of theory with moored meter data collected in Onslow Bay, North Carolina are made during upwelling favorable summertime wind conditions.

• Research Organization: Department of Marine Science and Engineering, North Carolina State University, Raleigh 27650
• OSTI ID: 7063985
• Journal Information: J. Phys. Oceanogr.; (United States), Journal Name: J. Phys. Oceanogr.; (United States) Vol. 10:12; ISSN JPYOB
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580500* -- Oceanography-- (1980-1989)
BAYS
CONTINENTAL MARGIN
CONTINENTAL SHELF
CONTINENTAL SLOPE
MATHEMATICAL MODELS
ONSLOW BAY
TIME DEPENDENCE
UPWELLING
VELOCITY
WIND