MetOcean-on-Demand for the US East Coast: Wave and Hydrodynamics Database

Abstract

The U.S. East Coast has the potential for offshore wind deployment and contribute to the energy demands of the area. A safe and cost-effective development of offshore wind farms requires detailed and accurate meteorological and oceanographic (MetOcean) analysis and, thus, a wave and hydrodynamic database has been produced along the U.S. East Coast. The high-resolution wave and hydrodynamic models are calibrated and validated against various NOAA measurements along the U.S. East Coast. The wave model open lateral boundaries are forced by spectral data from a global wave model. Wind forcing for both models were taken from CFSR wind fields, and the hydrodynamic model was also forced by atmospheric pressure field. Spatially and temporally-varying water level and depth-averaged currents were used to force the wave model. The hydrodynamic model was forced by tidal elevations at the boundaries. The model’s resolution varies from 15 km along the offshore boundaries to approximately 3 km near the coastline. Wave spectra resolution was of 25 frequencies and 16 directions. New wave model features are explored, including the effect of atmospheric stability on wave growth, the air-sea density ratio and the current impact on the wave growth rate. These processes are now included during the calibration process of the wave model. Hydrodynamic model results show good agreement with surface elevation measurements, with no bias and small errors. Results of the wave model show overall good results, although some overestimation of the extreme events is noticeable for the studied cases. The high-quality wave and hydrodynamic models developed within this work will serve as a MetOcean database for developers or alternatively as forcing for establishing local high-resolution (100s m resolution) models, i.e. for complex bathymetry at specific wind farm sites. Further work includes longer-term validations, data assimilation and assessment of other processes such as bottom friction and their impact on the estimation of extreme waves.