台風来襲時における高潮即時予測の精度と課題

Abstract

The real-time prediction of the storm surge at each port and coast is necessary to mitigate the coastal disaster. The storm surge can be computed in a few hours or less with a numerical model based on long wave approximation by an ordinary personal computer, while the maximum storm surge can be quickly calculated with a simple empirical equation based on the past storm records. In this paper, the storm surges at major points in east Seto Inner Sea, including Osaka Bay, and Tokyo Bay are predicted with the both methods and their results are compared with the measured. As the result, the magnitude of the storm surge by the empirical equation was sometimes larger than the measured and the time, of the peak was sometimes earlier by a few hours. For the exact computation of the storm surge, the spatial grid interval for the numerical model should be around 1.8km for the major points on the coast of Osaka Bay, 0.6km or less for the central Seto Inner Sea, and around 0.6km for Tokyo Bay The run of a typhoon should be started on south from the north latitude of 31 deg for the storm surge prediction of these bays.