Global Change Effects on the Distribution of Nutrient in the ECS, NW Pacific and Kuroshio Seas: A Tidal-Biogeochemical Coupling Model (II)

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Project title

Code/計畫編號

MOST103-2611-M019-015

Translated Name/計畫中文名

全球變遷因子對東海及西北太平洋黑潮海域營養鹽分布之影響：潮流生地化耦合模式(II)及海洋表面漂流浮標分析-以海上搜救為導向 (II)

Project Coordinator/計畫主持人

Hung-Jen Lee

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Marine Environmental Informatics

Website

https://www.grb.gov.tw/search/planDetail?id=8345010

Year

2014

Start date/計畫起

01-08-2014

Expected Completion/計畫迄

31-07-2015

Bugetid/研究經費

926千元

ResearchField/研究領域

海洋科學

"合併潮流到之前已發展完成且以平均環流為驅動力的三維海洋環流數值模式中，進而評估潮汐作用對東海鄰近海域的影響，其中特別有興趣的是潮汐作用加強了南東海長江水舌的擴散及環流。在夏季時如果在沒有潮汐作用的情形下，長江水舌擴散呈現一停滯、膨脹形狀的水池並且被限制在東海北部及黃海海域，相對於觀測資料顯示累積的水舌太偏向北方。而冬天的長江水舌擴散是被強烈的北北東季風所驅動並沿著中國海岸線往東南方向流動形成一股沿岸流，無論有無潮汐作用情形下大致符合觀測結果。本研究顯示加入潮汐作用力後之模式；尤其是夏季時更接近實際觀測，會位移台灣暖流到較低緯度、強化中國東南沿岸的上升流以及導引中國東南沿岸一帶的潮汐餘流。有三個現象改變是三位一體的，也就是說夏季時潮汐會引發海水離岸作用；冬季時，北北東季風會抑制台灣暖流到最小。因此，三個潮汐所引起的機制常常一起停止存在。無論如何，冬天的季風如果停止吹拂幾個禮拜，台灣暖流會再度出現，而三個現象緊密連接的機制也像夏季的情況一樣會再度運轉，在長江口南方溫鹽深儀探測和衛星觀測的資料將使潮汐環流藕合模式結果更為顯著。""Incorporating tidal currents into a previously validated, three-dimensional and subtidal circulation model, further we assess tidal effects on the circulation in and around the East China Sea. Of particular interest is the tide-enhanced Changjiang plume dispersal and circulation in the southern East China Sea. Without tides, the Changjiang plume in summer presents itself as a stagnant, expansive pool in regions bordering northern East China Sea and Yellow Sea, too far north and too accumulating relative to observations. The winter plume dispersal, pushed by the fierce north-northeast monsoon to follow China coastline southeastward as a coastal current, is more in line with observations with or without tides. Tides bring the model closer to reality especially in summer, shifting the Taiwan Warm Current to lower latitudes, enhancing upwelling off southeast China and inducing a southward tidal residual coastal flow off southeast China. The three changes appear in trinity. Tides also induce the observed seaward detachment of summer plume. In winter, the prevailing north-northeast monsoon suppresses the Taiwan Warm Current to the minimum. In consequence, the three tide-induced mechanisms often cease to exist altogether. However, if the winter monsoon is allowed to relax for a few weeks, the Taiwan Warm Current reappears and the three inseparable mechanisms begin to operate as in summer. CTD surveys and satellite observations south of Changjiang mouth bring our model findings to better lights."

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Global Change Effects on the Distribution of Nutrient in the ECS, NW Pacific and Kuroshio Seas: A Tidal-Biogeochemical Coupling Model (II)

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