| 摘要: | 眾多的合成孔徑雷達遙測影像、海流暨水溫觀測均顯示，內潮(internal tides)現象經常可見於南海北部(例如：Hsu et al., 2000; Ramp et al., 2005; Yang et al., 2005)。理論上，潮流流經海底峽谷、繞過島嶼或地形陡升海域，都可能造成層化海洋產生內潮波，以南海北部為例，由東向西行進的太平洋潮波，通過呂宋海峽進入南海時，因海檻地形而激發內潮向西傳播。1996 至2004 年間SCSMEX, KUDEX 和ASIAEX 計畫研究成果指出，南海北部以全日潮為主，全日與半日潮流振幅相當，半日潮以斜壓運動為主，全日潮則包含正壓與斜壓運動(Ramp et al., 2005; Yang et al., 2005)；Beardsley et al. (2004) 則指出，半日斜壓潮是在呂宋海峽被引起的，可向西傳播並經東沙群島抵達中國大陸南部陸棚淺海區，而全日斜壓潮卻是在南海北部引發的。基於以上觀測事實，本研究擬建立(1)北太平洋水平解析度1°/4 暨亞洲邊緣海與東北亞海域1°/8 巢化、雙向偶合環流模式，探討黑潮在呂宋海峽的變異、黑潮對南海北部環流的影響、及呂宋海峽深層海流的行為；(2)以前述模式結果為初始場，置入多重水平解析度(1/8~1/32 度)、垂直至少21 層的三維斜壓潮汐模式，探討南海全日與半日內潮的產生機制、正壓潮與斜壓潮能量收支平衡，以及內潮在南海北部陸棚上的淺化與破碎等行為。本計畫預計分三年執行，第一年預定分別完成北太平洋環流模式和斜壓潮汐模式，探討黑潮在呂宋海峽附近的變化並且校驗潮位模擬結果；第二年預定完成以上兩模式的偶合，探討南海內潮產生機制；第三年預定利用前述模式分析正壓潮與內潮能量轉換、內潮在南海北部陸棚上的淺化與破碎等行為。 Supports are requested for a numerical study on internal tides in the South China Sea in the next three years. Internal tides are easily identified from satellite remote-sensing images and field observations in the northern South China Seas (see, e.g., Hsu et al., 2000; Ramp et al., 2005; Yang et al., 2005). Internal tides are usually generated in a stratified ocean in association with tides when tidal currents incident over topographic rises and submarine ridges. A typical, and also striking, case is that when the westward-propagating tides pass through the Luzon Strait, the meridional bottom sill across the Luzon Strait triggers internal waves propagating into the northern South China Sea (SCS). Results analyzed from observations indicate that tidal sea levels are predominantly diurnal and tidal currents are mixed with semi-diurnal and diurnal components in the northern SCS; the semi-diurnal tidal currents are mainly baroclinic while the diurnal tidal currents consist of barotropic and baroclinic (Ramp et al., 2005; Yang et al., 2005). The baroclinic semi-diurnal tides are presumably generated in the Luzon Strait, while the baroclinic diurnal tides might be formed in the northern SCS (Beardsley et al., 2004). To better understand the generation of internal tides and energy budget of barotropic/baroclinic tides in the SCS, this study propose to develop a 1°/4 and 1°/8 two way nested circulation model for the northern Pacific Ocean and a 1 °/8 to 1°/32, three-dimension, baroclinic tide model to study the aforementioned issues. The shoaling and breaking happened when internal tides propagate onto the shallow shelf south of China will be investigated by the model. The North Pacific Ocean model will be spun-up and the 3D baroclinic tide model will be established in the first year. Both model results will be compared and validated with observation data collected from other sub-projects. The North Pacific Ocean model results will be incorporated into the tide model as the initial condition in the second year. Hence the tide model can be used to study the internal tides in the northern SCS. The tidal energy budget and internal tidal wave breaking will be analyzed in the third year. 研究期間：9608 ~ 9707 |
