A study on the relationships between the wave height and the El Nio in the north area of the South China Sea

On the basis of the European Centre for Medium-range Weather Forecasts (ECMWF) 20 a wind field reanalysis data, the wave field of the north area of the South China Sea is calculated with the combination of the HIRHAM wind field model and the SWAN wave model. Then a significant wave height compared with the El Nio index to study the relationships between these variables. The following conclusions are drawn: (1) the wave height of the South China Sea has a strong seasonal variation, the wave height is much larger in winter than in summer; (2) in the South China Sea, the monthly average wave height of the north area has a negative correlation with the Nio3.4 index, most area of the South China Sea has a moderate correlation and the area between Taiwan Province of China and Philippines is highly correlated; and (3) in the strong El Nio years, the significant wave height in the north area of the South China Sea is significantly smaller than in other years; if the El Nio index variability is greater, the wave height decreases. In contrast, the significant wave height in the north area of the South China Sea is larger in the strong La Nia years.