| Summary: | 碩士 === 國立臺灣海洋大學 === 海洋環境資訊系 === 105 === The purpose of this study is to investigate rapid growth waves occurred in the Taitung Open Ocean by analyzing waves (2011-2015) obtained by the wave buoy deployed here by the Central Weather Bureau. The rapid growth waves were defined as the waves with significant wave height not only increased more than two times but also grew to at least 1.5 m in 6 hours. It was found that in this time period there were 51 incidents of rapid growth waves. It was found that most of the rapid growth wave events occurred in the winter season and that the main weather system associated with the rapid growth waves was the arrival of weather front followed by a cold continental high pressure, about 33.3% of the cases. During the rapid growth wave event, the wind and wave were mostly from the west–northwest. It was also found that the angle between the wind and wave direction decreased to 30-40 degrees, indicating these waves are due to local wind. By analyzing the wave period in the rapid growth events, it was found that the wave period increased as the wave grew rapidly. This study also investigated the relationship between the wave height and wind speed. The results indicated that the squares of the maximum wave height after the growth and the maximum wind speed in the event had a correlation coefficient of 0.87.
Comparisons of the rapid growth events in Taitung Open Ocean with those occurred in Hualien in the eastern coast of Taiwan showed that the former had fewer numbers of events annually than that in Hualien, about 12 versus 21. The main weather system associated with the rapid growth waves in these two stations were the arrival of weather front followed by a cold continental high pressure. However, the events in Taitung open sea lasted longer and had higher peak wave height.
Since the significant wave height in Taitung Open Ocean are always higher than that in Hualien waters, it is more difficult to achieve the rapid growth wave as defined. Hence the number of incidents of rapid growth waves was less than that in Hualien waters.
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