Prediction of Typhoon Storm Surge Flood in Tokyo Bay Using Unstructured Model ADCIRC Under Global Warming Scenario

Abstract

The possibility of a major typhoon and its likely effects on Tokyo Bay have been estimated using an atmosphere-ocean-wave coupled model for future global climate conditions, based on the Intergovernmental Panel on Climate Change, Special Report on Emissions Scenarios (IPCC SRES) A1B scenario. In addition, the basin- to channel-scale unstructured grid hurricane storm surge model, Advanced CIRCulation (ADCIRC), has been used to determine the risk of storm surge flood in coastal areas, particularly on the Koto Delta, where inundations would most likely reach maximum levels during a strong typhoon. The system uses a high-resolution (down to 45 m) representation of regional geometry, bathymetry, and topography and emphasizes the seamless modeling of processes including those of storm surge, stormtide inundation, and river flow. The numerical experiment is validated by comparing the temporal and spatial distribution of water elevation and inundation with results obtained using a one-way coupling model of storm surge and wave activity. The simulation results show that the maximum tide level may exceed 4 m on the north side of Tokyo Bay, and surge-induced floods may extend throughout most of the Koto Delta region. And the validation results indicate that the sea-land interaction and river flows may significantly affect the depth and increase of extent of inland inundation.