• Title/Summary/Keyword: coastal current

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The Influence of Oceanic Conditions on the Occurrence of Cochlodinium polykrikoides Blooms in the East Sea (동해안의 Cochlodinium polykrikoides 적조 발생에 미치는 해황의 특성)

  • Shim, Jeong-Min;Hwang, Jae-Dong;Jeong, Chang-Su;Lee, Yong-Hwa;Jeon, Kyeong-Am;Kwon, Kee-Young
    • Journal of Environmental Science International
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    • v.19 no.12
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    • pp.1385-1395
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    • 2010
  • Harmful dinoflagellate Cochlodinium polykrikoides blooms have been frequently occurred in coastal areas of the East Sea since 1995. We compared the oceanic conditions in years 1995, 2001 and 2003 when the C. polykrikoides bloom was strong, and in years 1998 and 2004 when the C. polykrikoides bloom was not appeared. We studied temporal and spatial variation of upwelling and geostrophic currents on the western channel of Korean Strait, an entrance of the East Sea. The period and occurrence area of C. polykrikoides bloom was depended on variation of upwelling in summer. In the distributions of geostrophic current, southward current was dominant near the coast in August, 1998 and 2000. Whereas northward current was dominant near and off the coast in August, 1995 and 2003 which the C. polykrikoides bloom was strong. When compared dominant phytoplankton of the coastal areas in each year, Kuroshio indicator species Proboscia alata and Chaetoceros affine were dominant, respectively, in 2001 and 2003 at every stations. However, the dominant species was variable at each coastal area in 1998 and 2000. In 2003, the abundance of Sagitta elegans which is known as the cold water indicator was low, but the abundance of S. enflata, warm water indicator, was very high in Gangneung compared to Sokcho. It seemed that the distribution of S. elegans is restricted by strong warm water current. In conclusion, it was estimated that the distribution of C. polykrikoides bloom in the coastal area of the East Sea was closely related with the strength of East Korea Warm Current and upwelling.

A Note on Water Masses and General Circulation in the Yellow Sea (Hwanghae) (黃海水 와 循環에 관한 考察)

  • Lie, Heung-Jae
    • 한국해양학회지
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    • v.19 no.2
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    • pp.187-194
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    • 1984
  • Water masses and circulation in the yellow Sea (Hwanghae) were briefly reviewed and synthesized. Water masses were classified into four types: Hwanghae Cold Water, Hwanghae Warm Current Water, Coastal Waters and Changjiang River Diluted Water. The Hwanghae Cold Water can be defined to have a salinity of 32.0∼33.0% and a temperature below 10$^{\circ}C$, based on long-term hydrographic data and recent CTD casts (KORI, 1984). Concerning circulation, there exists a cyclonic gyre throughout the year in the southern part. In winter, the coastal current along the Chinese coast is very strong due to northerly or northwesterly winds and the Hwanghae Warm Current becomes weak as can be expected from a surface to bottom thermohaline front west of Cheju-do. Meanwhile in summer, the Changjiang River Diluted Water flows northeastward toward Cheju-do and the coastal current in the western part is greatly reduced. The northward current during summer in the southeastern Hwanghae has been accepted to be the Hwanghae Warm Current until now, coastal waters and the Hwanghae Cold Water in the central deep area, not a continuation of the Hwanghae Warm Current.

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A Study on the Plannings for the Sustainable Tourism Development of Korean Coastal Wetlands - Focused on Youngjong Island and its neighboring areas - (우리 나라 연안습지의 지속가능한 관광개발 방안에 관한 연구 - 영종도 주변지역을 중심으로 -)

  • Park, Tae-Yoon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.2 no.3
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    • pp.74-82
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    • 1999
  • This study is aimed to establish the development plannings for the sustainable tourism of Yongyoo Island and Mooeui Island, neighboring areas of Youngjong Island, for the conservation and environmentally friendly use of Korean coastal wetlands. The concepts of sustainable tourism is described. The current development status and its problems of Youngjong Island and its neighboring areas are analysed. The development plannings for sustainable tourism of Yongyoo Island and Mooeui Island are suggested as follows : (1) The small scale tourism development projects, which are able to represent region's own characteristics, instead of large scale ones, should be performed. (2) The participation of community people should be guaranteed at the beginning stage of the decision making processes for tourism development projects. Additionally, the profits of the development should be fairly distributed among community people. (3) The coastal wetlands should be conserved and their sewage disposal capacity should be protected by way of the minimization of reclamation. (4) The coastal wetlands should be developed into the tourist resorts utilizing migratory birds as tourism resources. In addition, the carrying capacity of the coastal wetlands, which is based on the current status of ecosystems and the Environmental Impact Assessment(EIA), should be calculated.

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Coastal-physical cceanographic aspects in relation to the tidal current power generation in the Uldolmok (울돌목 조류발전의 연안물리적 관점에서의 고찰)

  • Yum Ki-Dai;Lee Kwang Soo;Park Jin Soon;Kang Sok Kuh
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.516-519
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    • 2005
  • The pilot tidal current power plant is to be constructed at the Uldolmok between Chindo and Haenam, during next year. and extensive coastal engineering research works have been carried out. In this paper we describes some observation results of the tide and tidal current. as well as modeling work in order to investigate the tide and tidal current regime change in relation to the tidal current power plant (TCPP) construction. The special modeling skill in order to consider the turbine operation in the TCPP is developed and applied to the estimation for the flow regime change by the simple layout of the tidal current power plant.

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Coastal-physical cceanographic aspects in relation to the tidal current power generation in the Uldolmok (울돌목 조류발전의 연안물리적 관점에서의 고찰)

  • Kang Sok Kuh;Yum Ki-Dai;Lee Kwang Soo;Park Jin Soon
    • New & Renewable Energy
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    • v.1 no.2 s.2
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    • pp.73-78
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    • 2005
  • The pilot tidal current power plant is to be constructed at the Uldolmok between Chindo and Haenam, during next year, and extensive coastal engineering research works have been carried out. In this paper we describes some observation results of the tide and tidal current, as well as modeling work in order to investigate the tide and tidal current regime change In relation to the tidal current power plant [TCPP] construction. The special modeling skill in order to consider the turbine operation in the TCPP is developed and applied to the estimation for the flow regime change by the simple layout of the tidal current power plant.

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Bottom Friction on Mobile Coastal Beach (이동장 해저면에서의 마찰력)

  • 유동훈;이동수
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.4 no.2
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    • pp.63-71
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    • 1992
  • A solution method is developed for computing the bed shear stress driven by combined wave and current flow on a natural mobile coastal beach. An empirical equation is introduced to determine the shape of ripples formed on the natural sandy beach. The model being based on the Prandtl's mixing length theory, the effect of arbitrarily-angled interaction is included in the estimation of current velocity reduction and all numerical integrations are expressed by explicit approximate equations to improve the computation speed. In addition the computed sediment transport rates were compared with the measured values reported in literature. using the refined bottom friction model considering the ripple formation.

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Analysis of Financial Ratios of the Korean Coastal Passenger Shipping Company and Proposal for Improving their Business Performances (한국 연안여객선업체의 재무상태 분석과 경영개선 방안)

  • 노창균
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.8 no.1
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    • pp.1-14
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    • 2002
  • This paper discusses the analysis of financial ratios of the Korean coastal passenger shipping company 1997 and 2000. Coastal passenger shipping company shows a very high ratio of the fixed-assets because these shipping company own relatively expensive ships. The current debts are composed of short-term borrowings and lease and the ratio of the current debts is rather high considering to the size of shipping company. The equity ratio of passenger shipping company has recently been decreased, but the debt ratio has been increased. Both the profitability and activity ratios have grown worse in recent years. In order to improve the performance of coastal passenger shipping company, they should develop the leisure facilities and good items to attract travellers.

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Evaluation of Fluid Forces Acting on Offshore Structures Placed in the Vicinity of Underwater Shoal (수중 천퇴 인근에 설치된 해양구조물에 작용하는 유체력 결정에 대한 고찰)

  • Chun, In-Sik;Min, In-Ki;Sim, Jae-Seol
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.2
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    • pp.136-145
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    • 2007
  • When waves propagating over an underwater shoal break at the top of the shoal, wave heights are drastically decreased in the downstream breaking zone, but a secondary current shooting downstream with strong velocity can be induced by the breaking waves themselves. In the case that an offshore structure is placed in the breaking zone, the estimation of wave farce purely based on the visible wave height may cause an under-design of the structure. Thus, for the safe design of the structure, the breaking wave induced current should be necessarily considered in the comprehensive estimation of design load. In the present study, Boussinesq equation model to calculate the wave height distribution and breaking wave induced current was set up and applied to the scheme of a hydraulic model test previously undertaken. Based on the results of the Boussinesq model, fluid forces acting on the model structure were calculated and compared with the experimental results. The importance of the breaking wave induced current was quantitatively assessed by comparing fluid forces with or without current.