Long-term hazard analysis of destructive storm surges using the ADCIRC-SWAN model: A case study of Bohai Sea, China

Destructive storm surges bring large waves and unusually high surges of water to coastal areas, resulting in many human casualties and significant economic loss. In this study, an unstructured grid wave-current coupled model was developed for the Bohai Sea, China, using the ADCIRC (ADvanced CIRCulation) and SWAN (Simulating WAves Nearshore) models to simulate 32 disastrous storm surge events from 1985 to 2014. The return storm surge elevation in the Bohai Sea using the Gumbel method is obtained and compared with previous results. It is found that extratropical cyclones and cold air play important roles in storm surges in the Laizhou Bay and have more influence than tropical cyclones. Moreover, the joint probabilities of surge and wave are obtained by using the Gumbel logistical model. The results show that the effect of waves in surge-wave joint probabilities on the central basin of the Bohai Sea is more significant than that on the Bohai Sea coast. By establishing a system to assess the relative risks of storm surges in the Bohai Sea, it is found that Laizhou Bay is in the greatest danger.