A numerical investigation on the energetics of a current along an ice-covered continental slope
<p>The Chukchi Slope Current is a westward-flowing current along the Chukchi slope, which carries Pacific-origin water from the Chukchi shelf into the Canada Basin and helps set the regional hydrographic structure and ecosystem. Using a set of experiments with an idealized primitive equation n...
Main Authors: | , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2023-03-01
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Series: | Ocean Science |
Online Access: | https://os.copernicus.org/articles/19/289/2023/os-19-289-2023.pdf |
Summary: | <p>The Chukchi Slope Current is a westward-flowing current
along the Chukchi slope, which carries Pacific-origin water from the Chukchi
shelf into the Canada Basin and helps set the regional hydrographic
structure and ecosystem. Using a set of experiments with an idealized
primitive equation numerical model, we investigate the energetics of the
slope current during the ice-covered period. Numerical calculations show
that the growth of surface eddies is suppressed by the ice friction, while
perturbations at mid-depths can grow into eddies, consistent with linear
instability analysis. However, because the ice stress is spatially variable,
it is able to drive Ekman pumping to decrease the available potential energy
(APE) and kinetic energy of both the mean flow and mesoscale eddies over a
vertical scale of 100 m, well outside the frictional Ekman layer. The rate
at which the APE changes is determined by the vertical density flux, which
is negative as the ice-induced Ekman pumping advects lighter (denser) water
upward (downward). A scaling analysis shows that Ekman pumping will dominate
the release of APE for large-scale flows, but the effect of baroclinic
instability is also important when the horizontal scale of the mean flow is
the baroclinic deformation radius and the eddy velocity is comparable to the
mean flow velocity. Our numerical results highlight the importance of ice
friction in the energetics of the slope current and eddies, and this may be
relevant to other ice-covered regions.</p> |
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ISSN: | 1812-0784 1812-0792 |