Flow of grounded abyssal ocean currents along zonally-varying topography on a rotating sphere |
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Authors: | Gordon E Swaters |
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Institution: | 1. Department of Mathematical and Statistical Sciences , Applied Mathematics Institute, University of Alberta , Edmonton, AB , Canada, T6G 2G1;2. Institute for Geophysical Research , University of Alberta , Edmonton , AB , Canada, T6G 2G1 gswaters@ualberta.ca |
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Abstract: | A steady nonlinear planetary–geostrophic model in spherical coordinates is presented describing the hemispheric-scale meridional flow of grounded abyssal currents on a zonally-sloping bottom. The model, which corresponds mathematically to a quasi-linear hyperbolic partial differential equation, can be solved explicitly for a cross-slope isopycnal field that is grounded (i.e. intersects the bottom on the up slope and down slope sides). As a consequence of the conservation of potential vorticity, the abyssal currents possess decreasing thickness in the equatorward direction while maintaining constant meridional volume transport. There is a small westward zonal transport in the interior of these currents that results in westward intensification as they flow toward the equator. Conditions for the possible formation of a shock to develop on the up slope flank of the current are derived. |
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Keywords: | Grounded abyssal ocean currents Deep western boundary currents Planetary–geostrophic balance Sverdrup vorticity balance Topographically-steered flow Spherical geometry |
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