Analyses of ocean currents around Taiwan: Typhoon impacts and applications in patrol inspection and rescue

• Main Authors: Yuan-Chun Chang, 張元俊
• Other Authors: Jau-Ming Chen
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/9vb3b3

碩士 === 國立高雄科技大學 === 海事資訊科技系 === 107 === The establishment of the Coast Guard Administration, Taiwan, aims at executing patrol investigation and maritime rescue. One of the key elements to improve this administration is to have better understanding of the ocean currents around Taiwan. In this study, ocean currents around Taiwan observed by the Taiwan Ocean Radar Observing System (TOROS) are employed to analyze the impacts of typhoons on current variability around Taiwan. This study analyzed five typhoon cases during 2016-2017 with different tracks affecting Taiwan: two typhoons moving northward through the ocean off the east coast and off the west coast, and three typhoons making landfall through northern, central and southern Taiwan. For the typhoon moving through the ocean off the east (west) coast, its counterclockwise surrounding flows induce northeasterly/northerly (southwesterly/southerly) flows on its western (eastern) section off the eastern coast of Taiwan to suppress (enhance) the mainstream of the Kuroshio. For the typhoon cases moving northwestward through northern and central Taiwan can reverse the Kuroshio tributary flows to the north of Taiwan from eastward into westward, while a typhoon passing through southern Taiwan does not reverse the current direction over there. It appears that strong winds caused by a typhoon are effective to change ocean currents around Taiwan. This study also applied the TOROS data into the cases of patrol investigation and rescue, including personnel drowning, power loss of a ship, drifting of smuggled cigarettes. The analyses show that the TOROS data have good accuracy in delineating the drifting processes of these cases from the beginning to the ending positions. In particular, the drifting distance of the personnel drowning case matches well the spatial estimation by multiplying drifting time by current speed. These results demonstrate that the TOROS data can serve as useful information to assist the executions of patrol investigation and maritime rescue in the oceans surrounding Taiwan by the Coast Guard Administration.