應用小波轉換探討潮位與颱風暴潮特性之研究

Study on the Characteristics of Tidal Elevation and Storm Surge Using the Continuous Wavelet Transform

李汴軍(Beng-Chun Lee) ； 黃瓊珠(Chiung-Chu Huang) ； 莊士賢(Laurence Zsu-Hsin Chuang) ； 高家俊(Chia-Chuen Kao)

《海洋工程學刊》 8卷1期 (2008/06) Pp. 23-42

https://doi.org/10.6266/JCOE.2008.0801.02

摘要

本文利用小波轉換分析潮位與颱風暴潮資料，探討此二現象在小波能量之時間及頻率上的分佈特性。由潮位之小波能譜在時間上的分佈，可以判斷該觀測地區之最大潮差發生的時間；由平均小波能量在頻率上的分佈，小於頻率0.5 day^(-1)以下之低頻部份所佔的能量極少，顯示由氣象因素所引起的水位變化，對於潮位之調和分析的影響極小。在颱風暴潮之小波能量方面，得知頻率在1 day^(-1)以下的平均小波能量，其能量曲線與暴潮水位在時間上的分佈相似。因此根據暴潮之小波能量分佈，可以精確的獲得最大暴潮發生的時間；同時由小波能量變動量之變化也可以推算颱風暴潮對岸邊影響的時間。

關鍵字

小波轉換 ； 分潮 ； 颱風暴潮

並列摘要

This paper adopts wavelet transform to study the phenomena of tidal elevation and storm surge based on the observed tidal data. The characteristics of space and frequency distributions of these two phenomena can be revealed by the wavelet energy. The wavelet energy of the tidal distribution in the time evolution is able to determine the maximum difference of tide occurring time for the observation location. Due to the energy parts less than 0.5 day^(-1) are very small magnitude from the low frequency, it is demonstrated that the variations of water elevation induced by the meteorological factor can be neglected from the harmonic analysis. If the wavelet energy frequency is less than 1 day^(-1), the distributions of storm surge graph are similar to that of energy curve. Therefore, according to the wavelet energy distribution of surge, it can acquire accurately the time of the occurrence of max surge. Meanwhile, it can reckon the influence time of storm surge on shore from the variety of the wavelet energy.

並列關鍵字

wavelet transform ； tide component ； storm surge