Storm waves during Typhoon Cobra (Halsey’s typhoon) in December 1944

A coupled-process based tide-wave-surge model has been used to simulate Typhoon Cobra in December 14-19, 1944, also best known as the Typhoons of 1944 or Halsey’s Typhoon. The typhoon information of location and direction that were provided to admiral Halsey was not accurate and the third fleet operating 480 km east of Luzon in the Philippine Sea sailed into the center of the typhoon. As a result, the ship was wrecked by strong winds of 87 kt, lowest air pressure of 907 hPa and very high seas. This typhoon resulted in the establishment of Joint Typhoon Warning Center (JTWC) in Hawaii. The model was constructed with fine-mesh finite element model covering the whole South China Sea with inclusion of the Java Sea and adjacent marginal seas and the Philippine Sea. Approximate mesh sizes in the region of interest were formulated as a few tens of meters and the bathymetry of the tidal flat area was described, thus enabling a detailed representation of component in tidal characteristics in the modelled tidal regime. Typhoon and meteorological forcing inputs for the period 13-20, December 1944 are prepared via blending of ECMWF-20C as background meteorological conditions and Holland type vortex typhoon fields. The water elevation determined from the estimation of the Japanese National Astronomical Observatory (NAOTIDE) database was imposed at the tidal open boundary. Time-series outputs of storm waves are produced showing maximum significant wave heights of 12-15 m along the typhoon track.