Wave Climate Changes in Bohai Sea Related to the East Asian Circulation Oscillations over the Last Sixty Years

Researching on wave climate change is the key to understanding the dynamic processes of the ocean when climate has changed. Bohai Sea is located on the northern edge of the East Asian Circulation, and the characteristics of wave climate stage change in this area has been influenced in long-term wind change. Multi-scale variability characteristics of wave climate from 1950 to 2011 are studied based on NCEP reanalysis data. Wave climate in the Bohai Sea during 1950 to 2011 have been simulated by SWAN model. Results showed that:the significant wave height decreased in past 62 years; wave direction increased and wave period changed smoothly. The average decrease in significant wave height was 0.3 cm/a, and the increase in the wave angle was 0.12°/a. The abrupt of significant wave height occurred around 1968; the abrupt change of wave direction occurred around 1960; the abrupt change of wave period occurred in 1965. Wave climate in Bohai Sea is mainly determined by oscillation of the large-scale atmospheric