台風9119号の解析と強風の分布について

Abstract

Typhoon 9119 (MIREILLE) making landfall at 1600 JST, Sept. 27, 1991 caused high wind disaster through Kyushu and Tohoku Districts. Characteristic features of this typhoon is investigated by pressure and wind analyses.Every ten-minute interval after landfall, pressure pattern is represented with the Schloemer's formula by the objective analysis method. In this analysis, we interporated the pressure data in the near center region of the typhoon by the time-space conversion, and the gradient wind is computed based on the computed pressure pattern.The gradient wind grew more intense after landfall and the intense wind region exceeding 50 ms-1 passed through the mountain part of Oita Prefecture and Hiroshima Bay, where the severe disasters by high wind were caused.About 2.5 hours after passing of the typhoon center, a pressure-dip with the maximum drop of 7.5 mb was observed through the northern part of Kyushu District and the western part of Chugoku District, and the life time of the dip exceeded 7.5 hours. At passing of the pressure-dip, peak gust of 20-40 ms-1 is observed, and it is considered that the investigation of this phenomenon is also important for a high wind disaster prevention work.