Title page for etd-0104112-104318


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URN etd-0104112-104318
Author Bo-Feng Wu
Author's Email Address No Public.
Statistics This thesis had been viewed 5566 times. Download 1627 times.
Department IAMPUT
Year 2011
Semester 1
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Analysis of observations and model simulation of swells in the water southwest Taiwan
Date of Defense 2011-08-18
Page Count 95
Keyword
  • WaveWatch Ⅲ
  • Steepness function
  • Wave spectrum
  • Swell
  • Wind wave
  • Abstract   Freak waves suddenly strike the southwest of Taiwan, may cause damages of coastal structures, tourist facilities and endanger maritime navigation. The prediction of swells and large waves is under development. In order to improve out understanding of the characteristics of swells, this study analysis data collected from a nearshore weather bouy and a coastal wave station. The Wave Watch 3 model is applied with several wind fields, and compared results with that of AVISO.
      The results show that (1) Waters in southwest of Taiwan, in the northeast monsoon season, the peak wave spectral energy tends to sift from short period to longer period, whereas in the southwest monsoon season, the spectrum of energy varies rapidly and is stronger. During the passage of typhoons, swells from the southern tip of Taiwan show stronger energy in the early stage and weaken gradually, on the other hand, swells from the northern tip of Taiwan show increasing energy spectrum to a peak value. The wave energy diminished after typhoon passed Taiwan Strait. (2) The patterns of wave spectrum are related to the winds. A single peak pattern is usually caused by the local winds. A double peaks wave spectrum suggests both local wind and remote forcing. The lower frequency energy is due to swells. (3) In order to separate the swells from the wind waves in the case of double peaks wave spectrum, two methods are applied. For the no typhoon period, a modified ‘P-M spectrum’ is useful as well as is the ‘derivative energy spectrum’. For the typhoon period, only the later method provides reasonable results. (4) Based on the analysis of separated wave spectrum, the ratio of occurrence is 65% wind wave and 35% swell in the normal days. The ratio varies during typhoon period. (5) The comparisons of Wave Watch 3 model output with AVISO data suggest that the forcing of QSCAT/NCEP Blended wind provides a better result.
    Advisory Committee
  • Chung-Pan Lee - chair
  • Chien Hua - co-chair
  • Guan-Yu Chen - co-chair
  • Yu-Huai Wang - advisor
  • Files
  • etd-0104112-104318.pdf
  • Indicate in-campus at 0 year and off-campus access at 1 year.
    Date of Submission 2012-01-04

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