Numerical simulation of wave field in the South China Sea using WAVEWATCH III

Abstract

Wave fields of the South China Sea (SCS) from 1976 to 2005 were simulated using WAVEWATCH III by inputting high-resolution reanalysis wind field datasets assimilated from several meteorological data sources. Comparisons of wave heights between WAVEWATCH III and TOPEX/Poseidon altimeter and buoy data show a good agreement. Our results show seasonal variation of wave direction as follows: 1. During the summer monsoon (April–September), waves from south occur from April through September in the southern SCS region, which prevail taking about 40% of the time; 2. During the winter monsoon (December–March), waves from northeast prevail throughout the SCS for 56% of the period; 3. The dominant wave direction in SCS is NE. The seasonal variation of wave height H _s in SCS shows that in spring, H _s ≥1 m in the central SCS region and is less than 1 m in other areas. In summer, H _s is higher than in spring. During September-November, influenced by tropical cyclones, H _s is mostly higher than 1 m. East of Hainan Island, H _s>2 m. In winter, H _s reaches its maximum value influenced by the north-east monsoon, and heights over 2 m are found over a large part of SCS. Finally, we calculated the extreme wave parameters in SCS and found that the extreme wind speed and wave height for the 100-year return period for SCS peaked at 45 m/s and 19 m, respectively, SE of Hainan Island and decreased from north to south.