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Characteristic Analysis of the Tidal Residuals' Mid/Long-period Components Using a Wavelet Method

웨이블릿방법을 이용한 조위편차 성분의 중·장주기 특성 분석

  • Kang, Ju Whan (Dept. of Civil Engineering, Mokpo National University) ;
  • Kim, Yang-Seon (Dept. of Civil Engineering, Mokpo National University) ;
  • Shim, Jae-Seol (Operational Ocean Science and Technology Department, Korea Institute of Ocean Science and Technology)
  • 강주환 (목포대학교 토목공학과) ;
  • 김양선 (목포대학교 토목공학과) ;
  • 심재설 (한국해양과학기술원 특성화연구본부)
  • Received : 2013.05.22
  • Accepted : 2013.08.19
  • Published : 2013.08.31

Abstract

Fourier analysis and a wavelet method were carried out to elucidate the characteristics of tidal residual components in coastal waters. The result of Fourier analysis shows tide-induced and monsoon-induced residuals are conspicuous at the short period and mid period, respectively. The tidal residuals were decomposed by period from 3 hours to 8 months and the characteristics of their components were shown by reconstituting them with short periods less than 24 hours, mid-periods between 1 day and 16 days and long periods longer than 1 month. The tidal residuals in the short period, i.e., tide-induced components, being based on the tidal elevation prediction errors, appear in the West Sea with high tidal ranges and do not have much seasonal fluctuation. Additionally, the period of typhoon induced surge ranges more or less than 12 hours. The mid-period components were clearly generated mainly in the West Sea during the winter and largely affected by monsoon. Accordingly, the pure surge height components were concentrated on the mid-period and had clear features for each coastal waters. The long period components show similar characteristics at all stations and are considered to stem from variations of mean sea levels.

해역별 조위편차 특성을 규명하기 위해 푸리에(Fourier)해석과 함께 웨이블릿(Wavelet)분석을 실시하였다. 푸리에 해석결과 조석관련성분은 단주기, 계절풍 성분은 중주기에 분포하고 있음을 보이고 있다. 웨이블릿 분석에서는 3시간 주기부터 8개월 이상 주기까지 주기별로 분리한 후 24시간 이내의 단주기, 1일~16일의 중주기 및 1개월 이상의 장주기로 구분하여 주기별 특성을 파악하였다. 24시간 이내 단주기 성분의 조위편차는 조석예측 오차에 기인하고 있으며 조차가 큰 서해안에서 크게 나타나고 있다. 또한 태풍에 의한 주기성분은 대략 12시간 정도인 단주기에 집중적으로 나타나고 있다. 1일~16일 주기의 중주기 성분의 경우 서해안에서 동절기에 특히 활성화되고 있어 계절풍 영향이 매우 큰 것으로 나타나고 있다. 따라서 순수한 해일고 성분은 중주기에 집중되고 있으며 해역별로 뚜렷한 특성차를 보이고 있다. 또한 모든 해역에서 유사하게 나타나고 있는 장주기 성분은 평균해수면 변화에 의한 것으로 파악되고 있다.

Keywords

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Cited by

  1. Appearance of Tide-surge Interaction along the West/South Coasts vol.26, pp.6, 2014, https://doi.org/10.9765/KSCOE.2014.26.6.352
  2. Frequency Analysis on Surge Height by Numerical Simulation of a Standard Typhoon vol.28, pp.5, 2016, https://doi.org/10.9765/KSCOE.2016.28.5.284
  3. Decomposition of Water Level Time Series of a Tidal River into Tide, Wave and Rainfall-Runoff Components vol.10, pp.11, 2018, https://doi.org/10.3390/w10111568