SST Ensemble Experiment-Based Impact Assessment of Climate Change on Storm Surge Caused by Pseudo-Global Warming: Case Study of Typhoon Vera in 1959

To evaluate future changes in storm surge caused by global warming, dynamical downscaling was conducted using the Weather Research and Forecasting model for Typhoon Vera under present-and future-climate conditions and storm surge simulation using the Coupled Model of Surge, Wave, and Tide. The present-climate experiment entailed dynamical downscaling using data from the Japanese 55-year Reanalysis project as the initial and boundary conditions, and the future-climate experiments entailed downscaling considering future changes simulated through sea-surface temperature ensemble experiments using the Meteorological Research Institute Atmosphere General Circulation Model. The characteristics of the downscaled typhoon agreed well with the Best Track, and the future changes in the typhoon characteristics were as follows: intensification of the central pressure, delayed decline in the high-latitude area, and westward track migration. Present-climate storm surge simulation executed using these downscaling results after correcting for the track error agreed with the observed surge, but the storm surges under future-climate conditions were underestimated because of differences in the typhoon track and surface roughness. Storm surge simulations were conducted using an empirical typhoon model; the results suggest a storm surge of 26 cm (average of the ensemble) at Nagoya Port, which is located in the innermost region of Ise Bay.