This paper adopts wavelet transform to study the phenomena of storm surge based on the observed tidal data. The characteristics of space and frequency distributions of this feature can be revealed by wavelet energy. This analysis demonstrates when weather conditions are stable, the changes of the wavelet energy deviation closes to zero. However, the wavelet energy of storm surge increases along with the typhoon approaching. If the wavelet energy frequency is less than 1 day-1, the distributions of storm surge graph are similar to that of energy curve. Wavelet energy distribution of surge can therefore acquire accurately the time of the occurrence of max surge. Meanwhile, it can reckon the influential time of storm surge on shore from the variety of the wavelet energy.
Taiwan is located between the tropical and subtropical regions of the northwest Pacific Ocean. It is the path of the typhoon during summer. Generally speaking, there are 3 to 4 typhoons invade and attack Taiwan Waters in averaged through the years. However, the trend has increased in recent years. The eastern water of Taiwan faces the Pacific Ocean directly, where the typhoon is activity over there. When the typhoon hit eastern Taiwan, it is able to generate storm surge due to the water level rising within the typhoon scope. And storm surge makes big damage over the coast area. Therefore, storm surge phenomenon over Taiwan waters is a major product of typhoon. The processes of change of this kind of storm surge wave motion have three steps which are forerunner surging, storm surge, and resurgence. The forerunner surging is made by the typhoon swell approaching coast region in advance to make the increment of the slowness of water level.