The annual extreme elevations in the Jiaozhou Bay and adjacent sea during 1989-2005 are simulated with a high-resolution three-dimensional hydrodynamic storm surge model considering the atmospheric pressure and wind. The simulated annual extreme elevations agree well with the observed data at two tide gauges within the domain of interest in the selected typhoon events, with the root mean square errors less than 12cm. Sensitivity experiments show that the atmospheric factors, such as the variation of sea surface pressure and the radius of the maximum wind, play a remarkable role on the simulation and prediction of storm surges. Both the astronomical tides and storm surges affect the annual extreme elevations in 14 cases of the 17 ones selected. The check water level of 50-year return period varies from 2.0 to 3.5m and its isolines are nearly parallel to the isobaths. The value larger than 3.2 m mainly appears in the northeast of the Jiaozhou Bay.
The knowledge and prediction of long term sea level variation, and the associated determination of check water level are important for both the scientific research and practical activities. The sea surface elevation, especially the extreme elevation during a storm surge, is critical for coastal engineering strategies. A storm surge accompanied by severe waves and high sea surface elevation can damage the coastal area heavily, and leads to distinct changes of the marine environment. As a semi-closed area located at the northwest of the Yellow Sea (Fig. 1b), the Jiaozhou Bay is vulnerable to storm surges, as surrounded by an important economic district, the research of the storm surge is of great significance (Zhang, 2004). The real time sea surface elevation is a combined result of the oscillations in different temporal and spatial scales. Some researches have been done on the interaction of the long-term sea level variations and instantaneous sea surface elevation in the East China Sea (ECS for short, hereafter).
