Numerical Modelling of Wind-Waves. Problem and Results

Abstract: Stochastic wind sea is an intermediate small-scale physical process responsible for the state of the atmospheric boundary layer and the water upper layer, having dynamics of all scales. To describe behavior of this system, one could use the mathematical formalization based on a spectral evolution model for wind waves. To this end, it needs a well-designed numerical model derived from the principal physical equations. On this way certain theoretical problems take place. At present some of these problems are solved, that gives possibility to construct a lot of numerical wind wave models, the latest version which was proposed in Polnikov(2005). With the aim of assessing real merits of the new source function proposed in the mentioned paper, the latter was tested and validated by means of modification the well known model WAVEWATCH-III. Assessment was done on the basis of comparing the wave simulation results obtained by both models for a given wind field against the buoy data gotten in the three oceanic regions. Estimations of simulation accuracy were obtained for three parameters of wind waves: significant wave height, Hs, peak wave period, Tp, and mean wave period, Tm. Comparison of these estimations between the original and modified model WAVEWATCH was fulfilled and analyzed. Advantage of the modified model was revealed, consisting in an increase of simulation accuracy for Hs in 1.2-1.5 times for more than 70% of buoys considered. Additionally, it was found that the speed of calculation was increased in 15%.