Boicourt, W. C. University of Maryland Center for Environmental Science, Horn Point Laboratory, boicourt@hpl.umces.edu
Valle-Levinson, A. C. Center for Coastal Physical Oceanography, Old Dominion University, arnoldo@ccpo.odu.edu
Lascara, C. Center for Coastal Physical Oceanography, Old Dominion University, lascara@ccpo.odu.edu
Roman, M. University of Maryland Center for Environmental Science, Horn Point Laboratory, roman@hpl.umces.edu
Burgett, R. Center for Coastal Physical Oceanography, Old Dominion University, burgett@ccpo.odu.edu

 
HYDRAULIC CONTROLS AND TROPHIC TRANSFER IN THE CHESAPEAKE BAY ESTUARY
 
Local convergent circulation features in the Chesapeake Bay are being examined as possible mechanisms for the observed enhanced material transfer from primary to secondary production. Among a variety of structures such as fronts, turbidity maxima, and residual eddies, we are focusing on the role of hydraulic controls in concentrating planktonic organisms as well as enhancing production. Although we have addressed the primary hydraulic control region near the Potomac River junction, we are finding that internal hydraulic processes are active over a variety of topographic features, including the Bay entrance region. High-resolution time series using an undulating towed vehicle, the SCANFISH, a Doppler velocity profiler, and moored instrumentation have been employed to examine the details of tidal variations in the flow and density structure over abrupt changes in topography. At the Bay entrance, lee waves with associated large vertical excursions of the pycnocline result from interactions of the combined tidal and gravitational circulations with three-dimensional transitions in width and depth of the channel. Lee waves also appear on flood tide at the primary control point, where inflowing water exits the broad Rappahannock Shoals and enters the narrow Deep Trough of the Bay. Here, the classical estuarine circulation appears to be choked, and the lower-layer inflow often resembles a true gravity current. The agreement of the observed flow and density structure with numerical model predictions helps establish the picture of a regional convergence with strong mixing and vertical transport.
 
Day: Thursday, Feb. 4
Time: 09:30 - 09:45am
Location: Hilton of Santa Fe
 
Code: SS04TH0930H