INVESTIGATION OF PARAMETRIC MODELS FOR ATMOSPHERIC PRESSURE, WIND SPEED AND WAVE HEIGHT IN A TYPHOON

Abstract

 This study shows characteristics of parametric models for atmospheric pressure, wind speed and wave height in a typhoon (or hurricane). The Myers expression and extended ones such as the Holland expression including a shape parameter B and an elliptic type distribution for typhoon-induced pressure distribution are used and a gradient wind model associated with any of these expressions is applied to wind speed estimation. Discernible difference is seen among pressure patterns changing from central pressure toward far-field pressure obtained by the models. As for wind speed, increase of B yields reinforcement of the maximum value and reduction of strong wind area. Additionally, introduction of either Super Gradient Wind (SGW) concept or an elliplic pressure distribution produces its strengthening. In cases where central pressure difference ∆Pc-dependent relation is used for the estimation of typhoon radius R, the maximum wave height in a typhoon calculated by either the Ijima et al. relation or the Young et al. relation is given by a function of both ∆Pc and moving velocity V and its highest value appears around the value of V = 45 km/h in ∆Pc and V space. SWAN provides a wave height pattern with the maximum value near the maximum wind speed area in a typhoon.