Seasonal Variations in Optical Conditions Associated with the Mobile Bay Outflow Plume.

摘要

River and estuarine outflow waters contain high loads of colored dissolved organic material (CDOM or gelbstoff), sediments, and biological matter with strong optical signatures. In regions with large, single point sources, interactions with ambient shelf waters are fairly simple. The buoyant outflow plumes tend to remain cohesive and become trapped against the contra solem coast. These plumes can extend for distances of more than 100 km along coast with characteristic widths of 5-15 km (internal Rossby radius of deformation) and thickness of a few 10's of meters. When winds turn to upwelling favorable, the plume waters are rapidly dispersed, mixing their optically important constituents across the shelf. Wind relaxation or a turn to downwelling favorable wind initiates a new along-coast plume. Such strong dynamic/optical interactions drive high variability in coastal optical character. The objective of this study is to examine this high dynamic variability in relationship to seasonal variations in forcing and constituent loading fields.