Effects of Environmental Changes on Ocean Circulation in the East China Sea (I)-1

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Project title

Code/計畫編號

NSC99-2611-M019-008

Translated Name/計畫中文名

東海長期觀測與研究(Ⅳ)---海洋環流與環境變遷數值模式之發展(I)及台灣鄰近海域海洋現象受大氣影響之探討-1

Project Coordinator/計畫主持人

Shih-Jen Huang

Funding Organization/主管機關

National Science and Technology Council

Co-Investigator(s)/共同執行人

李宏仁

Department/Unit

Department of Marine Environmental Informatics

Website

https://www.grb.gov.tw/search/planDetail?id=2134330

Year

2010

Start date/計畫起

01-08-2010

Expected Completion/計畫迄

31-07-2011

Co-Investigator(s)

Hung-Jen Lee

Bugetid/研究經費

1143千元

ResearchField/研究領域

海洋科學
大氣科學

"全球天文潮汐耗散超過3 兆瓦的潮汐能量，其中約1 兆瓦，是在淺水邊緣海被轉換為當地的海水斜壓運動，太平洋西方邊界東海、黃海及渤海是主要受到這些消散能量的海域。連續的潮汐運動，包括內潮和潮汐，將會影響二次潮環流和長江水舌擴散分布。在本研究中，我們將潮流加入先前被驗證過三維的東海環流模式中，並用它來評估潮汐如何影響長江之水舌擴散分布。一般而言，結果顯示夏季的潮流會使得長江水舌更往南方及外海擴散，而不是往北擴散，理論上潮流是由模式的南方及東方邊界加入，應該會使得長江水舌擴散更往北。但，事實正好相反，冬季潮流模式也使得長江水舌往南方發展。因此，潮流效應使得東海模式更接近觀測。另外，在研究長江水舌擴散分布的過程中，可能要考慮internal Rossby radius of deformation 與模式格點大小(grid size)的關係，如果internal deformation radius 小於格點大小，那在解析動力行為上將會有失真的情形發生。因此，本研究首要工作將改善原被驗證過的三維的東海環流模式的格點大小，加強數值模式解析長江水舌擴散分布的能力。""Global astronomical tides dissipate more than 3 terawatts of tidal energy, among which about 1 terawatt is through conversion to baroclinic motions preferably in shallow marginal seas. Being impinged upon by deep ocean tides from the east, the interconnected East China Sea, Yellow Sea and Bohai are at the receiving end of this conversion. Consequent tidal motions, including both internal and external tides, affect the subtidal circulation and Changjiang plume dispersal. In this study, we incorporate tidal currents into a previously validated, three-dimensional, subtidal circulation model (Lee and Chao, 2003), and use it to assess how tides affect the Changjiang plume dispersal. In general, the added summer tidal currents disperse Changjiang plume more southward and seaward rather than northward, whereas the winter tidal currents enhances the southward plume dispersal. Thus, tidal effects bring the model closer to reality. Further, the process of studying Changjiang plume dispersal, the issue concerning the relations between internal Rossby radius and magnitude of the model grid size could be considered. If the model grid size is greater than internal Rossby radius, if any, it is occurred that the results of the tide-circulated model could be substantially distorted. Therefore, the first goal of the present study is to improve grid size of the previously validated, three-dimensional, subtidal circulation model in order to enhance the resolutions of it on the Changjiang plume dispersal."

Keyword(s)

環流
潮汐
江水舌擴散
circulation
tide
Changjiang plume dispersal

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Effects of Environmental Changes on Ocean Circulation in the East China Sea (I)-1

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