All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 134 17 3
PDF Downloads 22 6 0

Topographically Controlled Flow Around a Deep Trough Transecting the Shelf off Kodiak Island, Alaska

View More View Less
  • 1 NOAA Pacific Marine Environmental Laboratory, Seattle, WA 98105
Full access

Abstract

Current measurements core the axis of a deep trough normal to the coast and from the adjacent shelf show that the mean flow is barotropic and follows depth contours, conserving potential vorticity, to form a cyclonic vortex or meander over the trough. The data are interpreted as an example of an inertial Taylor-Proudman column on the continental shelf. The scale of the topographic variations dominates the potential vorticity balance and a simple steady-state numerical model is in good agreement with the data when the vorticity balance approaches the limit U · BH = 0. Streamlines following isobaths converge over steeper topography and current speeds are nearly proportional to the local topographic gradient. Estimates from the data support this behavior and indicate that the ∼20 cm s−1 mean current around the trough is driven by a typical cross-shelf-averaged velocity scale of ∼5 cm s−1.

Abstract

Current measurements core the axis of a deep trough normal to the coast and from the adjacent shelf show that the mean flow is barotropic and follows depth contours, conserving potential vorticity, to form a cyclonic vortex or meander over the trough. The data are interpreted as an example of an inertial Taylor-Proudman column on the continental shelf. The scale of the topographic variations dominates the potential vorticity balance and a simple steady-state numerical model is in good agreement with the data when the vorticity balance approaches the limit U · BH = 0. Streamlines following isobaths converge over steeper topography and current speeds are nearly proportional to the local topographic gradient. Estimates from the data support this behavior and indicate that the ∼20 cm s−1 mean current around the trough is driven by a typical cross-shelf-averaged velocity scale of ∼5 cm s−1.

Save