碩士 / 國立臺灣海洋大學 / 海洋環境資訊學系 / 96 / This study investigates rapid growth wave phenomena occur at seas near the Northeast coast. The wave and meteorological data are obtained from two data buoys, located at Longdong and Kueisan Island, owned by the Central Weather bureau. In the present study, the rapid growth waves are defined as the waves with significant wave height increase at least two folds in 6 hours and the significant height is no less than 1.5 m after the growth. The rapid growth wave events can be dangerous to fishing boats or fishermen who fish on the coast. In this study, 314 and 24 events were identified for the Longdong and Kueisan Island, respectively. The significant wave height, significant wave period, atmospheric pressure, wind speed and direction were studied.
It was found that the rapid growth wave event often occurs in the winter, from December to February, at Longdong and in the months from February to April and the months of September and November in Kueisan Island. For these two locations, the significant wave period first decreased before the growth of wave height. Then, during the rapid growth period, the atmospheric pressure and wave period gradually increased. For the wind conditions, the wind blew from various directions for the Longdong station before the wave growth. Then, the wind turned northerly or northeasterly as the wave grew rapidly. On the contrary, the northerly or northeasterly wind prevailed for the Kueisan Island before and during the rapid growth period. By averaging wind speeds measured in the growth events over all the growth events, it was found that average wind velocity at Kueisan Island was higher than that at the Longdong station by about 2 m/s. Under the influence of the same weather system, the Kueisan Island’s wave growth events occurred about 2-4 hours later than that of the Longdong station. The ratios of wave height afterward and before the growth events measured at the Kuiesan were also smaller than that of Longdong.
This study also identified 7 events with waves grew more than 6 times in 6 hours, but none at Kueisan Island. For these high ratio events, it was found that they occurred after the passage of meteorological front with intense pressure gradient accompanied with strong northeasterly wind. For these events, the maximum significant wave height was proportional to the maximum wind speed found in each event. About 2-4 hours after the wind turned northeasterly, the wave height grew significantly.
| Identifer | oai:union.ndltd.org:TW/096NTOU5282008 |
| Date | January 2008 |
| Creators | Ya-Ping Huang, 黃雅萍 |
| Contributors | Cheng-Han Tsai, 蔡政翰 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 74 |
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