Similar analysis for the two summer upcoast observations indicates an entirely different result, i.e., the section transports are quite unrelated to local wind stress. During the summer upcoast flow regime the forcing of the fluctuations observed in the current in south Texas is less clear but significantly associated with the longshore surface slope and the wind stress components at various frequencies. However, variance in the currents in central Texas and central Louisiana in summer is highly coherent with sea level gradients. It appears likely that the strong southeasterly winds characteristic of south Texas in summer elevate the water level in the Texas coastal bend, which provides an eastward pressure gradient to drive fluctuations in the upcoast flow off central and east Texas and the Louisiana coast. Because these analyses identify wind forcing as a primary driving force, we simulated the observed variability in the current with a simple model of the along-plume momentum balance.
Satellite imagery shows that fronts are a major feature in temperature-salinity distribution.
Imagery also shows that the size and morphology of the Atchafalaya and Mississippi River sediment plumes are controlled primarily by river discharge and wind direction and speed. Both plumes can change rapidly with major wind direction shifts. In the biological characterization studies, several conclusions were made. Small phytoplankton, primarily cyanobacteria dominate numerically. Data suggest that the coastal plume ecosystem, with very high nutrient inputs and high production, is also highly dependent on regenerative processes typical when small phytoplankton dominate.