Studies of hydro-meteorological return level in Beibu gulf

Using WRF, SWAN, and ECOM numerical models, this paper calculated one hundred return levels of wave height, wave period, wind speed, current velocity, and surge level based on the influence of tropical cyclones on Beibu gulf during 1992~2011. It is found that the occurring time of extreme wave height and extreme surge level is different. Besides, the distribution characteristics of 100 a return period of wind speed, wave height, wave period, current velocity and surge level have been researched. Wave height is high up to 10.5 m in the south, decreasing northward. Wave period's distribution is similar to wave height, and the biggest value is up to 11.5 s in the south, decreasing northward. In the distribution of wind speed, there are two big value areas up to 39 m/s in the north and south of Beibu gulf, and midwestern areas are relatively small. Current velocity in the rim of Beibu gulf is bigger than medium area, and it is the biggest in the east, up to 300 cm/s nearby Dongfang city. Surge level is generally bigger than 160 cm, and it is up to 340 cm in the northern area, decreasing southward.