• Title/Summary/Keyword: overtide

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방조제 건설에 따른 낙조우세적 조류특성의 변화

  • 강주환
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 1997.10a
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    • pp.90-94
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    • 1997
  • 조석파가 연안해역에 접근하게 되면 바닥마찰이나 수심의 감소에 따른 조위의 비선형 효과 및 육지와의 경계부분에서 발생하는 흐름의 곡률 등 여러 가지 요인에 의해 파의 진행에 변화가 야기되며 (Pugh,1987), 이에 따라 동일 천문조의 간섭에 의해 나타나는 overtide, 또는 2개 이상의 천문조간 상호 간섭에 의해 나타나는 compound tide와 같은 천해조가 발생하게 된다. (중략)

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Periodic characteristics of long period tidal current by variation of the tide deformation around the Yeomha Waterway (염하수로 인근에서 조석 변형과 장주기 조류성분의 변동 특성)

  • Song, Yong-Sik;Woo, Seung-Buhm
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.23 no.5
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    • pp.393-400
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    • 2011
  • The mass transport is very complicated at the area which has the macro tide and complex geometry such as Gyeonggi bay. Especially, the long period current has a strong influence on the estuarine ecosystem and the long-term distribution of substances. The long period current is caused by several external forcing, whose unique characteristic varies spatially and temporally. The variation characteristics of long period current is analysed and its generation mechanism is studied. The tidal nonlinear constituents such as overtide and compound tide are generated due to nonlinear interaction and it causes mean sea level setup. The tidal wave propagating up into estuary is transformed rapidly by decrease of cross-sectional area and depth. Therefore the mean sea level is getting rise toward upriver. The high and low tide level is similar between down-river(Incheon) and up-river(Ganghwa) during neap tide when the tidal deformation is decreased. The tidal phase difference between two tidal stations causes a periodic fluctuation of sea level difference. The low water level of Ganghwa station during spring tide does not descend under EL(-)2.5 m, but the low water level of Incheon fall down under EL(-)4.0 m. The variation of tidal range and its sea level are increased during spring tide. It is found that the long period current $M_{sf}$ is quite similar to that of sea level difference between the two tidal stations. It means that the sea surface inclination caused by the spatial difference of tidal deformation is important forcing for the generation of long period current.

Tides and Currents of Kamag Bay in July-August 1994 (1994년 7-8월 가막만의 조석 및 해류)

  • LEE Jae Chul;CHOO Hyo Sang;LEE Kyu Hyong;CHO Kyu Dae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.28 no.5
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    • pp.624-634
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    • 1995
  • Tides at both of northern and southern entrances of Kamag Bay were compared by deploying tide gauges for 18 days during July-August 1994. To examine the response of the inner bay to the tidal waves through both entrances, a current meter was moored at the eastern pan of the inner bay. Current meter mooring failed at the northern entrance (Yosu) while the current data was collected for only 5 days at the southern site (Songdo). Maximum range was 357 and 352 cm at Yosu and Songdo, respectively. Respective amplitudes for M2, S2 Kl O1 tides of 95.5, 48.8, 20.5, 14.0cm at Yosu and 93.6, 47.2, 21.3, 13.1cm at Songdo yielded the form numbers of 0.23 and 0.24, respectively, both of which belong to the predominantly semidiurnal tide, Contributions from the overtides and compound tides were less than $4\%^ at both sites. Differences in Greenwich phase of major partial tides between two sites were negligible. Maximum speed of tidal current was about 100cm/sec at the southern entrance and about 40cm/sec at the inner bay. Residual current speed was 17cm/sec southwestward at the southern entrance and 0.9cm/sec southeastward at the inner bay. Temporal change in current at the inner bay showed that the wind had a significant influence upon the circulation in Kamag Bay.

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