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Signorini & Cavalieri 2002
Signorini, S.R. and Cavalieri, D.J. (2002). Modeling dense water production and salt transport from Alaskan coastal polynyas. Journal of Geophysical Research 107: doi: 10.1029/2000JC000491. issn: 0148-0227.

A three-dimensional primitive equation model was used to assess the effects of dense water formation from winter (1996/1997) polynyas on the ambient stratification, salt transport, and circulation in the vicinity of Barrow Canyon. The model, which includes ambient stratification and bottom topography, is forced by time-varying surface heat flux, surface salt flux, and coastal flow. The influence of sea ice drift on the circulation and salt transport is also analyzed by prescribing ice water stress at the sea surface. The surface fluxes and ice drift are derived from satellite observations (Special Sensor Microwave Imager (SSM/I) and NASA scatterometer (NSCAT) sensors). The coastal flow (Alaska coastal current), which is an extension of the Bering Sea throughflow, is formulated in the model by using a wind-transport regression. One set of experiments was forced by strong and persistent polynyas, simulated by 20-day averaged heat and salt fluxes originating from the largest events. In this set of experiments both strong and weak steady coastal currents were imposed. The amount of salt exported from the generation area depended on the strength of the current. Another set of experiments was forced by weaker and less persistent polynyas using time-varying forcing. The experiments with time-varying polynya forcing were conducted with two ambient vertical stratifications, one representing fall conditions and one representing winter conditions. The amount of salt retained on the shelf was found to be quite sensitive to the initial stratification. Weaker vertical stratification promotes a deeper mixed layer, which develops 20 times faster than the horizontal advective timescale of the coastal current, thus increasing the residence time of the salt generated by the polynya on the shelf. The time-varying northeastward coastal current, combined with the offshore Ekman transport, can export 29--73% of the salt produced by polynyas upstream of Barrow Canyon, depending upon the ambient vertical stratification. The inclusion of ice water stress in the model makes the coastal current much wider due to the resulting offshore Ekman transport and also doubles the amount of salt exported.

BACKGROUND DATA FILES

Abstract

Keywords
Oceanography, Physical, Ice mechanics and air/sea/ice exchange processes, Oceanography, Physical, Upper ocean processes
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
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