UC San Diego

A performance assessment of the WaveWatch III (WW3) Ocean Wave Model in the Pacific Basin is conducted by comparing spectral model output to observational data from 13 drifting, GPS-based wave buoys in the mid-latitudes of the Northern Pacific. The observational array captured significant wave heights exceeding 12m and wave conditions associated with extratropical cyclones generated off the coast of Japan. While most model comparison studies use data from buoys moored near coastlines, the drifting array used in this work provides a unique opportunity to study cross basin storm and swell propagation. Although there is good agreement between the bulk parameters measured by the buoys and modelled in WW3, discrepancies in the timing of storm propagation lead to model-data inconsistencies. Arrival biases up to 10 hours and significant wave height discrepancies of 4m are documented. Additionally, at high-frequencies, the wave energy density modelled in WW3 is higher than the buoy measurements. Model-data biases in this study are postulated to be associated with errors in the wind-forcing field.