Modelo numérico de Olas

The Wave Model

Hourly fields of 96 hours of wave forecast, corresponding to the most recent forecast hour. The forecast hours are 00 Z, 06 Z, 12 Z and 18 Z and the products are estimated to be available at H + 4.5 hours. All heights are expressed in meters. The significant height is inferred in the model from the total energy of the waves. It resembles the characteristic height that an experienced observer visually estimates in a wave field and is the most widely used proxy measure of the field. However, it should be noted that individual waves can exceed significant height (ideally just over 13% of the waves) and even under normal conditions, an individual wave could double this height. The peak direction is the mean direction at the frequencies containing the maximum energy and is, in general, close to the direction of the maximum. The period of the energy peak or dominant period is the one corresponding to the frequencies that contain the maximum energy.

Austral-WWIII is the SHN/SMN implementation for the Southern Oceans and South Atlantic of the NCEP/NOAA WAVEWATCH III ® 3.14 third-generation wave model (Tolman, 2009). The domain allows representing wave generation and propagation in the Southern Oceans and the South Atlantic up to 15° S with a spatial resolution of 0.5° in latitude and longitude. Smaller islands and coastal features, which are obstacles to wave propagation, are represented as sub-scale obstructions (Chawla and Tolman, 2007).

Forecasts are updated four times daily with wind fields and air-water temperature contrast predicted by NCEP's GFS system, currently at T574 spectral resolution. This represents, in geographical terms, a little more than 1/5° (about 25 km). The operational resolution of the T382 GFS (approximately 35 km) was used in the initial calibration and validation. The NCEP analysis included in the 00Z GFS updates the ice field in the wave model daily.