- 期刊
利用海岸攝影機影像遙測瘋狗浪之研究
A Study on the Measurement of Coastal Freak Waves
摘要
瘋狗浪（freak wave）是海中突然發生的大浪，它大都在海洋中出現，也頻繁出現於海岸邊，對民眾從事海域遊憩活動帶來很大的危害風險。過去對瘋狗浪的研究大都採用數值方式進行，觀測研究甚少，主要是因為瘋狗浪不知發生於何時何地，很難觀測。本研究於海岸邊設置光學影像監視站，並發展一個影像處理方法與浪花流量與穿越速度計算方法，藉以判識瘋狗浪之發生，驗證結果顯示準確性可達八成以上，與過去實際發生意外事件之比較也相當一致。另外，分析結果也發現，海岸瘋狗浪之發生與入射波高未具有高度相關性，這代表瘋狗浪之發生除入射波浪外，尚有其它影響因子。本研究發展之瘋狗浪監測與分析技術可廣泛應用於各地，藉以蒐集更多瘋狗浪資料，對於掌握瘋狗浪特性與預警模式之建置帶來很大之助益。
並列摘要
Freak wave is a wave with large wave height generated suddenly. It mostly occurs in the sea, however it also occurs frequently in the coast. Many people drop into sea due to coastal freak wave attacked in Taiwan. In the past, most of the studies on coastal freak waves were carried out with numerical simulations because of lack of field data. This study aims to develop a measurement and analysis method for coastal freak wave. It is based on the image process technique. The proposed image process method derives the shape of the splash trigger by coastal freak water. The flow rate and throw speed of the splash were estimated. The parameter Flood Hazard (FH) was used to identify the coastal freak wave. The verification results show that the accuracy of the identification of the coastal freak wave is more than 80%. The result is also agreed with actual accidents reported in media. In addition, the analysis found that the occurrence of coastal freak waves is not only correlated with incident waves. The wave interaction with structure plays an important role for the generation of coastal freak wave. The measurement method for coastal freak waves developed in this study is helpful for establishment of warning system for coastal freak waves.