Mixing Estimates of a Surface Trapped Coastal Current
Abstract
Despite the important role of mixing in controlling the along-shelf transport, dispersion and fate of river plumes, very few mixing estimates have been done, especially in the far field region of a river plume. A three month-long (April-May-June, 2015) field program to investigate mixing of the Chesapeake Bay Plume (CBP) was conducted off Virginia and North Carolina coasts (USA), which included shipboard surveys, measurements using a REMUS (AUV), 13 moorings and 2 Wire Walkers. This intense survey provided detailed measurements of the velocity structure and stratification of the CBP, with complementary information provided by realistic simulations from a primitive equation numerical ocean model (ROMS). Here mixing of the CBP is estimated from both observations and results from numerical simulations, using a simple model, which relates the time-rate of change of salinity within the plume to the redistribution of salinity by (1) vertical and (2) horizontal shears, and (3) entrainment (bulk mixing term). Finally, the relative roles of each term (1-3) in controlling the change in buoyancy of the plume is calculated, and how these can be modified under different wind conditions.
- Publication:
-
American Geophysical Union, Ocean Sciences Meeting
- Pub Date:
- February 2016
- Bibcode:
- 2016AGUOSEC13B..06M
- Keywords:
-
- 4217 Coastal processes;
- OCEANOGRAPHY: GENERALDE: 4528 Fronts and jets;
- OCEANOGRAPHY: PHYSICALDE: 4558 Sediment transport;
- OCEANOGRAPHY: PHYSICALDE: 4568 Turbulence;
- diffusion;
- and mixing processes;
- OCEANOGRAPHY: PHYSICAL