Skip to main content
padlock icon - secure page this page is secure

Free Content Tidal mixing and cross-frontal particle exchange over a finite amplitude asymmetric bank: A model study with application to Georges Bank

Download Article:
Tidal mixing, internal wave bores, and cross-bank particle transport over a finite amplitude asymmetric bank are examined using a two-dimensional primitive equation ocean model with Mellor and Yamada (level 2.5) turbulent closure. Driven by the surface M2 tide, the model results show that tidal mixing exhibits temporal and spatial asymmetries on southern and northern flanks of the bank. It is strongest near the bottom around maximum on-bank tidal flow as a result of gravitational instability when denser water is advected upslope over lighter water. A sharp thermal depression occurs on the steep northern flank, which produces large current shear and strong tidal mixing throughout the upper 50 m of the water column. Dissipation also exhibits a strong tidal variation, with the largest values (of order 10-5 W/kg) occurring near-bottom around maximum on- and off-bank tidal flow. Dissipation generally decreases upward, with a distinct phase lag in the vertical. Fluid particles are advected upslope near the bottom in the upper slope region (depth <150 m) on both flanks, with some particles moving across the tidal mixing fronts near the bottom. The near-bottom residual Lagrangian current is opposite in direction to the residual Eulerian current on the northern flank due to strong nonlinearity over the steep bottom slope. The mean upslope advection of fluid particles near the bottom on both flanks is consistent with model passive tracer experiments, suggesting that strong tidal forcing of a stratified fluid over the bank can provide one physical mechanism responsible for high concentrations of nutrients and hence phytoplankton at the fronts on Georges Bank. The model predictions of eddy viscosity and turbulent dissipation rates are in good agreement with estimates based on recent current and microstructure measurements made on Georges Bank.

30 References.

No Supplementary Data.
No Article Media
No Metrics

Document Type: Research Article

Publication date: November 1, 1998

More about this publication?
  • The Journal of Marine Research, one of the oldest journals in American marine science, publishes peer-reviewed research articles covering a broad array of topics in physical, biological and chemical oceanography. Articles that deal with processes, as well as those that report significant observations, are welcome. Biological studies involving coupling between ecological and physical processes are preferred over those that report systematics. The editors strive always to serve authors and readers in the academic oceanographic community by publishing papers vital to the marine research in the long and rich tradition of the Sears Foundation for Marine Research. We welcome you to the Journal of Marine Research.
  • Editorial Board
  • Information for Authors
  • Subscribe to this Title
  • Purchase The Sea
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more