A Numerical Model of Typhoon Surge Along the Coast of Taiwan

Abstract

The storm surge associated with a typhoon approaching Taiwan is one of the main causes of floods that frequently occur in the low land areas in certain exposed coastlines. Every year typhoons strike Taiwan, especially from June to October. In the past, typhoon surges have caused a lot of damages. A numerical prediction of typhoon surge in the seas around Taiwan is developed. The model is based on the hydrodynamical-numerical method. Air pressure gradient and wind stress are considered as the driving forces for the typhoon surge in this model. Here a circular storm is taken as the typhoon model. The wind stress and bottom friction stress are also computed by means of parameterization. In this model the bottom topography plays a great role. In the calculation the sea water is considered as a homogeneous medium. The Typhoon Tim in 1994, the Typhoon Doug in 1994 and the Typhoon Herb in 1996 are selected for case studies to verify this numerical model. These typhoons, which had different wind forces, passed Taiwan along different paths. Thus the effect of different typhoons can be studied.