Journal of Geophysical Research是美國地球科學協會(AGU) 主辦的13個與地球科學研究相關的期刊之一，所有期刊的編輯群定期從最新出版的論文裡挑選具重要貢獻的地科研究成果並刊載於期刊網頁和協會週刊EOS。2011年即將結束之際，本校海洋研究所詹森副教授及其博士後研究員邱銘達博士主導、與海洋研究所王胄教授、美國華盛頓大學連仁杰教授和中央大學錢樺助理教授合著的論文”Sources of baroclinic tidal energy in the Gaoping Submarine Canyon off southwestern Taiwan”獲該協會選為”焦點論文”(AGU Research Spotlight)。該論文以研究船「海研一號」的探測資料結合海洋數值模式探討高屏海域「高屏峽谷」裡強烈內波的能量來源，論文指出，從呂宋海峽來的內波在高屏峽谷外遭遇由臺灣海峽南部來的內波，透過彼此複雜的共振機制產生一股由峽谷開口向峽谷頭的強大內波能量(見附圖)，強烈的內波在陡峭的峽谷地形上產生強烈的垂直混合，甚至可能將高經濟的櫻花蝦從峽谷深處推上表層海洋利於漁民捕捉。(刊登於JGR網站的報導見 http://www.agu.org/cgi-bin/highlights/highlights.cgi?action=show&doi=10.1029/2011JC007366&jc=jc ; 論文見 http://www.agu.org/pubs/crossref/2011/2011JC007366.shtml )
高屏峽谷及附近的內波能量通量(彩色箭頭)分佈顯示高能量的內波(紅色) 自呂宋海峽和臺灣海峽南部來，匯集後形成一股內波能量由峽谷開口沿著峽谷走向而上。(郭天俠繪製)
詹森副教授（左）與邱銘達博士（右）Title: Interacting ocean waves explain powerful sea floor canyon flows
Off the southwestern coast of Taiwan the Gaoping Submarine Canyon meanders in a giant backwards “S” as it stretches southwestward toward the South China Sea. In the canyon, a 200-m-deep cut into the seafloor that lies 300 m below the sea’s surface, the waters carry an usually large amount of internal tidal tidal power—9.1 MW from the canyon’s mouth to its head. Along with the strong flows a region of enhanced vertical mixing sits at the canyon’s head. Researchers had previously attributed the anomalous flows to internal waves pushing through the Gaoping Canyon, though the source of the energy remained an open question. When tide-driven waves pass over a sudden change in seafloor topography, the shift in pressure triggers gravity waves (known as internal waves) that propagate through the ocean’s interior. Using a three-dimensional model of the surrounding ocean, Chiou et al. (2011) isolated the likely source of the internal waves. The authors found that the powerful waves travelling through the Gaoping Canyon were not generated on site. Instead, they spawned at the nearby Taiwan and Luzon straits, each the site of a 6000 m change in relief. However, these remote waves were not enough to fully explain the energy seen in the flows in the Gaoping Canyon. From their model, the authors found that, at the head of the canyon, a large standing wave was amplifying other incoming waves. The authors suggest this standing wave was formed by one of two mechanisms: either the internal waves from the Taiwan and Luzon straits were positively interfering, or the Luzon Strait waves were interfering with other Luzon Strait waves that had previously reflected off the steep walls of the Taiwan Banks. The authors suggest that this standing wave is also responsible for the enhanced vertical mixing seen near the Gaoping Submarine Canyon. — Colin Schultz, AGU’s Editor/Writor.
(Reported by JGR Site:http://www.agu.org/cgi-bin/highlights/highlights.cgi?action=show&doi=10.1029/2011JC007366&jc=jc ;Publication in http://www.agu.org/pubs/crossref/2011/2011JC007366.shtml )
Colored arrows indicate the energy flux of the internal tide flowing in and around the Gaoping Canyon, with warm colors denoting high flux and cool colors low flux. The internal waves are heavily influenced by steep drops in the sea floor at the Taiwan and Luzon straits. Photo Credit: Sen Jan. (Summarized by Colin Schultz, AGU’s Editor/Writor)
