Surface wave analysis based on a hydrodynamic modeling system for the Delaware coastal environment

Kukulka, TobiasCoastal surface gravity waves play a role in sediment transport, coastal erosion, storm surge inundation, ship traffic safety, and the dispersal of nutrients and larvae. This study investigates surface gravity waves in the Delaware Bay and adjacent coastal region, employing a hydrodynamic modeling system. The model is based on a coupled application of the Regional Ocean Modeling System (ROMS) and Simulating Waves Near-shore (SWAN) within the coupled-Ocean-Atmospheric-Wave-Sediment Transport (COAWST) modeling framework. Slow ocean currents and waves are simulated over a period from 2006-2012, which coincides with a period of buoy observations in the bay. Modeled sea surface height and significant wave height agree reasonably well with observations. Our analysis suggests that waves on the shelf are largely representative of remotely generated swell waves, except in the winter when offshore waves are more wind-driven. Waves in the bay are driven most importantly by local wind, although waves from the continental shelf may propagate into the bay near the bay mouth. Seasonal variation in wave statistics is linked to seasonal variations in wave forcing by wind and remotely generated swell. Relatively strong tidal currents also modulate wave periods and amplitudes of waves near the bay deep channel. This research is an important first step in better understanding the influence of coastal waves on biology, transport, erosion, and storm surges, by creating a climatology for waves in the bay and exploring the physical factors that control them.University of Delaware, School of Marine Science & PolicyM.S