A study of storm surge in radial sand ridges under sea level rising

Sea level rise would result in a serious threat to the coastal environment， and an important factor is the intensifying and increasing frequency of the storm surge. The relationship between storm surge and sea level rise is not linear according to related studies. The variations of tidal waves and water depth are found to be the two main causes. Radial sand ridges off the north Jiangsu are a particularly interesting area for studying this nonlinear interaction， as there exist a complex large geomorphic system and an astronomic tidal system. The paper summarizes the tide and storm surge characteristics in radial sand ridges， as well as the trend of sea level change. Then a two-dimensional coupled model of astronomic tide and storm surge is established for the East China Sea and the South Yellow Sea， by use of WRF model and Delft 3D storm surge model. The distributions of the maximum water level set-up and the high level change when sea level rises are analyzed， under the effects of two typical typhoons which have the same path and intensity. The analysis results show that the water level set-up decreases universally in the radial sand ridges when the sea level rises， and it is more significant at near shore than the open sea. While in the middle and south radial sand ridges， the enhancement of the astronomical high tide level caused by the sea level rising is stronger than the attenuation of sea level rising by the storm surge.