https://scholars.lib.ntu.edu.tw/handle/123456789/45276
Title: | 南海季風實驗整合計畫─(子計畫四)黑潮對南海北部環流之影響 | Authors: | 莊文思 | Keywords: | 黑潮;巴士海峽;南海;Kuroshio;Bashi Channel;South China Sea | Issue Date: | 1999 | Publisher: | 臺北市:國立臺灣大學海洋研究所 | Abstract: | 黑潮形成於呂宋東側,在往北運動時 首先經過太平洋與南海交接處之呂宋海 峽。由於黑潮本身為一具斜壓效應之西方 邊界強流,而呂宋海峽為一寬逾300 公里 之開口,在遭遇無側邊邊界之情況時,流 場本身必須調整,加以海峽東側地形變化 複雜,因此黑潮分流與波動都可能會發 生。 在南海季風實驗中,我們曾經於巴士 海峽放置多組ADCP 錨碇,所得之長期資 料除已正確標定黑潮分流進入南海之位 置,並瞭解其流量之大致分佈狀況。 黑潮分流進入南海後,以往之水文調 查均顯示出在南海北部有大尺度渦漩產 生。最近的數值模式結果更認為黑潮下游 (台灣東側)之週期變化與南海北部之渦 漩同步發生。因此可以合理認定,巴士海 峽對南海北部與台灣東部之海流變化,具 有決定性之影響。 在黑潮上游海區海洋動力學實驗 (KUDEX)整合型計畫中,我們負責長 期監測黑潮分流進入南海的情形,藉助於 多組位於巴士海峽之ADCP 與RCM 錨 碇,我們得以觀測此分流之季節性及年際 的變化情形,並得以更確切了解在巴士海 峽附近之水團分布與動力平衡變化。 Kuroshio, the western boundary current in the Pacific Ocean, originates from North Equatorial Current, forms a concentrated, northward flow east of Luzon Islands. The coast of Luzon ends at Luzon Strait, and the Kuroshio suddenly loses its lateral boundary support, till it feels the east coast of Taiwan 300 km downstream. The Kuroshio also meets rough topography at the opening of the Channel. Conceivably, the flow field must adjust itself by separation of flow and/or eddies in order to be remaining dynamically stable. Since late 1996, we have deployed a number of ADCP moorings in the deepest part of the Bashi Channel, as part of the SCSMEX program. Though we encountered many difficulties, mainly from exceptionally strong tidal currents down to at least 1000m depth, the data we collected over 1½ -year clearly showed a branch of Kuroshio exists in the Channel without significant seasonal fluctuations. After separation from the main stream, this branch of Kuroshio finds its way into the South China Sea. Past hydrographic surveys have identified different scale of 2 eddies which constitute the major circulation pattern in the junction of Taiwan Strait and northern part of the South China Sea. Recent model study by Y. Hsueh suggests that eddy spin off is associated with meandering of the Kuroshio main stream, and resulted in periodic motion further downstream, as shown in the WOCE PCM-1 measurements. In the KUDEX project, we are responsible for monitoring the branch of Kuroshio in the Bashi Channel. For the purpose of identifying the migrating of Kuroshio axis and the intermittent nature of the spin-off eddies, we have gained a comprehensive picture of the behavior of Kuroshio in the gap of Luzon and Taiwan, and provide a clue for the current variations in the South China Sea. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/29297 | Other Identifiers: | 882611M002013AP7 | Rights: | 國立臺灣大學海洋研究所 |
Appears in Collections: | 海洋研究所 |
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882611M002013AP7.pdf | 110.17 kB | Adobe PDF | View/Open |
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