| Summary: | 碩士 === 國立臺灣海洋大學 === 海洋環境資訊系 === 103 === This study investigated rapid growth waves occurred in the coastal water off Chiku, Tainan by analyzing wave information obtained by a wave buoy operated by the Water Resources Agency, Ministry of Economic Affairs. The rapid growth waves were defined as the waves whose significant wave height grew more than two times and attained at least 1.5 m in 6 hours of time. It was found that between July 2006 and December 2014, there were 258 incidents of rapid growth waves. The relationships between the meteorological conditions and the waves during the rapid growth period were also studied. It was found that between July 2006 and December 2014, there were 258 incidents of rapid growth waves and most of them occurred in the winter season followed by the fall season. The main weather system associated with the rapid growth waves was the arrival of cold continental high pressure. By analyzing the wave period in the rapid growth events, it was found that the wave period increased as the wave grew rapidly. During the rapid growth wave event, the wind was mostly from the north-north east and the wave from north-north west. 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. This study also investigated the relationship between the wave height and wind speed. The results indicated that the maximum wave height after the growth and the maximum wind speed in the event had a correlation coefficient of 0.80. This study further compared these events occurred in Chiku with those found near Liuchiu Island, Pingtung. The results showed that there were 36 rapid growth wave events occurred under the same weather system, mainly resulted from offshore typhoons or tropical depressions. It was also found that there were 86 incidents simultaneously occurred at Chiku and Penghu Islands. The majority of these events were the results of meteorological fronts accompanied by a cold continental high pressure.
|
|---|
