An Intercomparison of Swan and Wavewatch III Models with Data from NDBC-NOAA Buoys at Oceanic Scales

• Published in: Coastal Engineering Journal 2008-03, Vol.50 (1), p.47-73
• Main Authors: Ortiz-Royero, Juan Carlos, Mercado-Irizarry, Aurelio
• Format: Article
• Language: English
• Subjects: NDBC; NOAA; SWAN; third generation wave model; WAVEWATCH III
• ISSN: 2166-4250; 0578-5634; 1793-6292
• DOI: 10.1142/S0578563408001739

A simulation of wind-wave activity in the North Atlantic Basin, between June to August of 2002, has been performed using the SWAN model. The results of the simulations were compared with data obtained from the National Data Buoy Center and the results from NOAA's WAVEWATCH III (WW3) wave model. This study tested the applicability of the SWAN model at oceanic scales. The SWAN model was developed for coastal areas, but in version (40.11), spherical coordinates have been included in the code for oceanic applications. It was found that, in general, WW3 produces a somewhat better fit to the observations than SWAN. The same conclusion holds even when global scale WW3 results were used as boundary conditions in the SWAN simulations. Since the same wind forcing was used, we could conclude that this difference in significant wave height, H s , could be due to the way wind energy is transferred to wave energy and its dissipation due to whitecapping in the models. The wind input parameterization in WW3 [Tolman and Chalikov, 1996] shows a better response to relatively fast changes in wind speed than the parameterization of Komen et al. [1984] used in SWAN. Although comparison between buoy observations and model output tends to favor WW3 over SWAN in deep water, we argue that the ease of use of SWAN, together with the simplification offered by just having to learn to use one model, makes the SWAN model a good option for simulations all the way from deep water up to the near shore.