Effects of sea level rise on storm surges in the south Yellow Sea: A case study of Typhoon Muifa (2011)

Abstract

Changes in sea levels due to climate change are expected to alter storm surge intensities worldwide, disproportionately effecting coastal communities. In this study, we explored the impacts of future sea level rise (SLR) on storm surges within various numerical frameworks. The relative mean sea level rise (RMSLR) scenario for a period of 100-yr was applied using satellite altimetry of sea surface height and subsequently adjusted for the influence of glacial isostatic adjustment (GIA) using the ICE-6G/VM5a model. For comparison purpose, two additional RMSLR distributions under Representative Concentration Pathway (RCP) scenarios were also evaluated from climate system model (CSM) ensembles and GIA. These spatially variable RMSLR scenarios were then incorporated into a high-resolution storm surge model using elevated present-day water depths to solve for coupled tide–surge–wave processes. The performance of the model was validated using in situ measurements of astronomical tides, storm tides and ocean waves. Due to the significant variability in the spatial distribution of future relative mean sea level trends in the Yellow Sea, the simplified, uniform RMSLR scenario was found to alter the responses of storm surges. The amplification or attenuation of surge heights was not solely affected by the magnitude of sea level change itself, but also modulated by changing tidal ranges and waves due to SLR. The amplification effects of tidal ranges and nonlinearities within radial sand ridges in the south Yellow Sea tended to be underestimated under the uniform scenario, suggesting that the impacts of SLR on storm surges in this region may represent underestimates.