On the Momentum Balance of Tampa Bay

Abstract

The momentum balance for the density-driven, nontidal circulation of a partially mixed estuary is generally considered to be between the pressure gradient and vertical friction forces, the result being a two-layered, mean estuarine circulation often referred to as gravitational convection. All estuaries, however, tend to have geometric complexities that may alter this simplistic view. Here we apply a very high resolution, numerical circulation model to diagnose the momentum balance distributions throughout Tampa Bay, a partially mixed estuary on Florida's west coast. With resolution as fine as 20 m, the model resolves the channels, inlets, bridge causeways, and other geometric complexities that impact the momentum balance distributions. A point-by-point, three-dimensional momentum balance closure analysis demonstrates that while the general expectation for the nontidal estuarine circulation is met, the distribution of terms within the balance is more complex than the simplistic view when real geometries are considered. With Tampa Bay geometries being typical of many partially mixed estuaries, the results herein may also be of a more general nature.