Mixing Estimates of a Surface Trapped Coastal Current

Piero Mazzini, Rutgers University New Brunswick, New Brunswick, NJ, United States, Robert J Chant, Institute of Marine and Coastal Science, New Brunswick, NJ, United States, John Wilkin, Rutgers University, New Brunswick, NJ, United States, Nicholas Nidzieko, University of California Santa Barbara, Department of Geography, Santa Barbara, CA, United States and Malcolm E Scully, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
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.
Back to: The Dynamics of Buoyancy Driven Flows in Estuaries and River Plumes and on the Continental Shelf III