NON LINEAR RESPONSE TO CYCLOGENESIS IN SEMI ENCLOSED WATER BODIES OF THE NORTHERN GULF OF MEXICO

Multi-year time series of hydrodynamic and meteorological data for two semi-enclosed water bodies along the northern Gulf of Mexico provide a detailed evaluation of the role of cyclogenesis in these otherwise low-energy, microtidal environments. Conditions associated with frontal overruns along the northern Gulf develop a continuum of responses in wave state. Data are also presented showing that when the fetch is at an optimal threshold, unexpected and extremely energetic, high frequency waves occur. A model is presented describing such events involving water level setup along neighboring lagoonal beaches and the removal of considerable volumes of sediment from the backshore by waves. Sediment transport pathways are also discussed Direct comparisons of wave characteristics from neighboring sites show a dramatic departure in energy levels during storms due to an influx of suspended sediments from an adjacent river, and subsequent attenuation of waves. The role of complex bathymetry at the entrance of these bays in causing pronounced shifts in the peak energy spectrum through bottom interaction is also evaluated. These data have potentially important implications for the evolution of these systems and the importance of episodic high-energy events in similar settings elsewhere.