Joint effects of wind and ice motion in forcing upwelling in Mackenzie Trough, Beaufort Sea
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- 作者：William J. Williams ; Eddy C. Carmack ; Koji Shimada ; Humfrey Melling ; Knut Aagaard ; Robie W. Macdonald and R. Grant Ingram
- 关键词：Shelf circulation ; Canyon upwelling ; Wind-stress ; Sea-ice ; Beaufort Sea ; 69– ; 73° ; N 128– ; 144° ; W
- 刊名：Continental Shelf Research
- 出版年：2006
- 出版时间：December 2006
- 年：2006
- 卷：26
- 期：19
- 页码：2352-2366
- 全文大小：1244 K
文摘
Mackenzie Trough, a cross shelf canyon in the Beaufort Sea shelf, is shown to be a site of enhanced shelf-break exchange via upwelling caused by wind- and ice-driven ocean surface-stresses. To characterize flow within the Trough, we analyze current meter mooring data and concurrent wind and ice velocity data from 1993 to 1996, and show CTD/ADCP sections from 2002. Mackenzie Trough is approximately 400 m deep and 60 km wide, but dynamically it is only 2–3 times the baroclinic Rossby radius at its mouth, and patterns of upwelling and downwelling flow within the canyon are similar to dynamically ‘narrow’ canyons. Large upwelling events within the canyon are associated with wind in the short ice-free summer season and with ice motion in winter. Ice motion does not necessarily reflect the wind-stress because of internal ice stresses that differentially block downwelling-causing ice motion. The asymmetry between upwelling and downwelling flow within the canyon combined with the predominance of upwelling-causing ice motion, suggests that Mackenzie Trough is a conduit for deeper, nutrient-rich water to the shelf.