Barotropic and baroclinic tidal currents on the Mackenzie shelf break in the southeastern Beaufort Sea

Abstract

[1] Tidal currents near the outer shelf break of the Mackenzie Shelf in the southern Beaufort Sea were examined using year-long (1987)(1988) current measurements from the upper ($35 m) and lower ($150 m) layers at four sites along the southeast (SS1), northeast (SS2), north central (SS3), and northwest (SS4) perimeter of the shelf. At all stations, semidiurnal currents were dominant, and upper layer currents were approximately double those observed in the lower layer. Maximum M 2 currents were observed above the sharp northeastern corner of the Mackenzie Shelf (6.0-7.5 cmÁs À1 ), while in the Mackenzie Canyon they were negligible. Diurnal currents were weaker and depth uniform; maximum K 1 currents (1.5-3.0 cmÁs À1 ) were found in the eastern part of the shelf. Diurnal and lower layer semidiurnal currents were in good agreement with those computed numerically by Kowalik and Proshutinsky [1994], indicating that these currents are essentially barotropic. In contrast, upper layer semidiurnal currents were mainly baroclinic. About 74% of the total energy of semidiurnal currents was associated with baroclinic coherent (phase-locked) tidal currents, while barotropic (12%), baroclinic incoherent (7%), and inertial (7%) components are the remaining semidiurnal currents in this area. High baroclinic generation coefficients (the ratio of locally generated baroclinic waves to barotropic waves) for stations SS2 and SS3 (about 7.0-8.0 in comparison with 0.3 for SS1 and SS4) located near the northeastern Mackenzie Shelf identify this region as a probable generation source of intensive internal tidal waves, which become then locally resonantly trapped between the shelf and the critical latitudes.

CO2 fluxes across the air‐sea interface in the southeastern Beaufort Sea: Ice‐free period

“…All are recognized sites of topographically enhanced upwelling during times of southwestward surface stress from wind or ice motion [ Carmack and Kulikov , 1998; Williams et al , 2006, 2008]. As demonstrated by Kulikov et al [2004], strong barotropic and baroclinic tidal currents occur in that area, which may induce important vertical mixing on the northeastern Mackenzie Shelf.…”

Canadian Coastal Seas and Great Lakes Sea Surface Temperature Climatology and Recent Trends

“…The main process generating these upwellings is the presence of northeasterly winds that, combined with isobath divergence, result in stronger mixing (Williams and Carmack 2008). Strong tidal mixing is also present in that area (Kulikov et al 2004). These cold waters are nutrient rich, sustaining enhanced primary production ).…”

Tide‐induced vertical mixing in the Laptev Sea coastal polynya

“…In spite of the recognized importance of baroclinic tides over the Arctic shelves [ Furevik and Foldvik , 1996; Dmitrenko et al , 2002; Morozov et al , 2008; Kulikov et al , 2004, 2010], there is a dearth of focused studies in shallow water of the Laptev Sea and the entire eastern Siberian shelf. Except numerical simulations by Kowalik and Proshutinsky [1994], tide‐induced vertical mixing in the Laptev Sea shelf during winter has not previously been considered as an efficient mechanism for facilitating property exchange across the SHL and promoting ventilation of the bottom layer.…”