Record Details
Time-Varying Across-Shelf Ekman Transport and Vertical Eddy Viscosity on the Inner Shelf
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Time-Varying Across-Shelf Ekman Transport and Vertical Eddy Viscosity on the Inner Shelf |
| Names |
Kirincich, Anthony R.
(creator) Barth, John A. (creator) |
| Date Issued | 2009-03 (iso8601) |
| Abstract | The event-scale variability of across-shelf transport was investigated using observations made in 15 m of water on the central Oregon inner shelf. In a study area with intermittently upwelling-favorable winds and significant density stratification, hydrographic and velocity observations show rapid across-shelf movement of water masses over event time scales of 2–7 days. To understand the time variability of across-shelf exchange, an inverse calculation was used to estimate eddy viscosity and the vertical turbulent diffusion of momentum from velocity profiles and wind forcing. Depth-averaged eddy viscosity varied over a large dynamic range, but averaged 1.3 X 10⁻³ m² s⁻¹ during upwelling winds and 2.1 X 10⁻³ m² s⁻¹ during downwelling winds. The fraction of full Ekman transport present in the surface layer, a measure of the efficiency of across-shelf exchange at this water depth, was a strong function of eddy viscosity and wind forcing, but not stratification. Transport fractions ranged from 60%, during times of weak or variable wind forcing and low eddy viscosity, to 10%–20%, during times of strong downwelling and high eddy viscosity. The difference in eddy viscosities between upwelling and downwelling led to varying across-shelf exchange efficiencies and, potentially, increased net upwelling over time. These results quantify the variability of across-shelf transport efficiency and have significant implications for ecological processes (e.g., larval transport) in the inner shelf. |
| Genre | Article |
| Identifier | Kirincich, Anthony R., John A. Barth, 2009: Time-Varying Across-Shelf Ekman Transport and Vertical Eddy Viscosity on the Inner Shelf. J. Phys. Oceanogr., 39, 602–620. |
