Transport and Mixing in Coastal Waters (cont'd)

The existence of such structure within flow is not limited to coastal waters. On the open ocean, current-following floats, drifters, and remote-sensing data show numerous localized, coherent structures ranging from major currents like the Gulf Stream, to mesoscale phenomena such as rings and associated vortex structures, down to a variety of submesoscale vortical features such as filaments, squirts, and mushrooms.

Until recently, the usual method for studying transport in environmental flows has been a statistical approach, which assumes there is no structure within the flow, i.e., that mixing and transport is homogeneous. However, a complete lack of structure is generally the exception, not the rule. Previous studies which noted the existence of chaotic stirring have been limited in that they were predominantly qualitative and not quantitative. That is, structures within the flow were seen, but the precise amount of fluid or effluent transported could not be calculated.