Validation of Operational Global Wave Prediction Models with Spectral Buoy Data

Global wave predictions produced at two U. S. forecasting centers, Fleet Numerical Meteorology and Oceanography Center (FNMOC) and the National Centers for Environmental Prediction (NCEP) are evaluated with spectral buoy measurements. Previous validation studies of global wave models were based primarily on wave height data from operational satellite altimeters and moored in-situ buoys. Fewer comparisons of frequency spectra and directional wave properties have been reported. In this study, data from directional wave buoys are used to examine the fidelity of frequency-directional spectra predicted by WAM and WAVEWATCH III (WW3) at the operational centers. The buoys used in the comparisons include 3-meter discus buoys operated by the National Data Buoy Center (NDBC) and Datawell waverider buoys deployed primarily along the California coast by the Scripps Institution of Oceanography Coastal Data Information Program (CDIP). Only buoys located in deep water are used in the comparisons. Here, preliminary results are presented for two locations, Point Conception, California and Christmas Island. Model nowcasts of frequency spectra and mean wave direction are compared to buoy measurements over a six-month period from 01 October 2000 to 31 March 2001. Individual swell events were identified in the spectra from the three models and the buoy data. Predicted and observed swell frequencies and arrival directions are compared, as well as the total energy transported past the buoy over the duration of each individual event. Two separate implementations of the WW3 model generally outperformed WAM.