NUMERICAL SIMULATIONS OF TYPHOON 1821 BY THE WRF MODEL AND INVESTIGATIONS OF THE FAVORABLE WIND FIELD INDUCING THE STORM SURGE

Abstract

 We conduct the control experiment (CTL) and the virtual experiment which assumes Kii Peninsula is the ocean (NoBay) of the typhoon 1821 by the WRF model and investigate influences of the geography on the storm surge in Kobe city. The result of CTL shows favorable wind field inducing the storm surge and almost reproduces wind observation of AMeDAS data at Kobe Airport. On the other hand, the gradient wind applied on the Best Track Data is dominantly a westward wind and greatly different from the characteristics of AMeDAS data at Kobe Airport. The maximum 30-minute averaged wind speed in Kobe city of NoBay decreased by 6% compared to CTL. This suggests Kii Peninsula strengthens the wind around Kobe city. These results suggest the wind field by physical typhoon simulation including effects of the land is essential for the accurate assessment of storm surge risks.