Flow and mixing in Juan de Fuca Canyon, Washington
Abstract
We report breaking internal lee waves, strong mixing, and hydraulic control associated with wind‐driven up‐canyon flow in Juan de Fuca Canyon, Washington. Unlike the flow above the canyon rim, which shows a tidal modulation typical on continental shelves, the flow within the canyon is persistently up‐canyon during our observations, with isopycnals tilted consistent with a geostrophic cross‐canyon momentum balance. As the flow encounters a sill near the canyon entrance at the shelf break, it accelerates significantly and undergoes elevated mixing on the upstream and downstream sides of the sill. On the downstream side, a strong lee wave response is seen, with displacements of O(100 m) and overturns tens of meters high. The resulting diffusivity is O(10−2 m2 s−1), sufficient to substantially modify coastal water masses as they transit the canyon and enter the Salish Sea estuarine system.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 01, 2014
- Source ID
- 10.1002/2013gl058967
Entities
People
- Matthew H. Alford
- Parker MacCready
Organizations
- Office of Naval Research
- University of Washington