• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.483-490
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• 2002

A massive amount of marine clay produced as dredging of coast and sea bed is often dumped in open sea and filled in pond. The treatment of marine clay demand a large area and make fatal environmental problems for echo system. This research work intend to manufacture a light-weight landfill materials which are produced by mixing the dredged marine clay with various amount cement and foam. An extensive Uniaxial and Triaxial compression test are carried out to investigate the strength characteristics of the light-weight cement mixed marine clay with foam under various test conditions. The results indicated that the required unit weight has been achieved with negligible change after 28days curing time in water. It is also recognized that the compressive strength of light-weight landfill materials linearly decrease with increasing initial water content, and the rate of strength decrease with increasing initial water content in water curing was smaller than that of air curing Futhermore, the rate of strength decreased with increasing initial water content, however, the rate become smaller as cement content increased.

• 한국항해학회지
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• 제14권1호
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• pp.39-55
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• 1990

Numerical model simulations are conducted for the evaluation of the water level variation in and out of the harbor due to the development and improvement of a harbor. The method used for the numerical analysis is the hybrid element method which includes energy dissipation due to imperfect reflection at the shore boundary and friction at the bottom. The model also includes the radiation condition on the open boundary by the analytic formulation and is applied to a real harbor, Guryongpo Harbor at the east coast of Korea. The result of experiment within the selected wave frequency band shows that the amplification factor out of the harbor is more than 2.0 at 32 sec period and strong responses near 20 sec, 25 sec, 54 sec periods in the harbor. Moreover, simulation results indicate that other longer wave periods affect to the variation of water level and horizontal water particle velocity exist. Thus, it seems to be necessary to modify the planform and the design of the harbor structures for the coming development.

• 대기
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• 제28권1호
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• pp.53-67
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• 2018

This study examined the lake effect of the Yellow Sea which was induced by the Siberian High pressure system moving over the open waters. The development mechanism of the convective cells over the ocean was studied in detail using the Weather Research and Forecasting model. Numerical experiments consist of the control experiment (CTL) and an experiment changing the yellow sea to dry land (EXP). The CTL simulation result showed distinct high area of relative vorticity, convergence and low-level atmospheric instability than that of the EXP. The result indicates that large surface vorticity and convergence induced vertical motion and low level instability over the ocean when the arctic Siberian air mass moved south over the Yellow Sea. The sensible heat flux at the sea surface gradually decreased while latent heat flux gradually increased. At the beginning stage of air mass modification, sensible heat was the main energy source for convective cell generation. However, in the later stage, latent heat became the main energy source for the development of convective cells. In conclusion, the mechanism of the west coast heavy snowfall caused by modification of the Siberian air mass over the Yellow Sea can be explained by air-sea interaction instability in the following order: (a) cyclonic vorticity caused by diabatic heating induce Ekman pumping and convergence at the surface, (b) sensible heat at the sea surface produce convection, and (c) this leads to latent heat release, and the development of convective cells. The overall process is a manifestation of air-sea interaction and enhancement of convection from positive feedback mechanism.

• 한국해양학회지
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• 제7권2호
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• pp.59-73
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• 1972

The heavy minerals of a barred estuarine and lagoonal sediments along the North Carolina coast have been studied with more than one hundred samples. Currents, salinity, and pH exhibit well-developed gradients from the upstream parts of the estuaries on the west toward the open ocean on the east. Twenty- four heavy minerals were identified in sediments of the study area. However, less than half of these occur frequently and the remainder exist only in minor quantities or trace amounts. Heavy minerals usually comprise less than 1% of the sample but vary from sample to sample. The maximum amount of heavy minerals in sediments of sounds and estuaries is 2.4% and in sediments of Outer Banks is 16.7%. Opaque minerals range from 10 to 85% of the total heavy mineral assemblage. Garnet and sillimanite are relatively more abundant in the eastern part than the western part in the area. Garnet more abundant in the northern part than the southern part, whereas sillimanite is more abundant in the southern part than the northern part, because the garnet source is in the northern part and one of the sillimanite source is in the southern part in the study area. The results of heavy mineral study indicate that the source of sediments is the Blue Ridge and Piedmont crystalline complex, and Coastal Plain formations. Some portions of sediments are transported from the Atlantic Ocean by the landward currents. They further indicate that the sediments of the Atlantic coast in the study area are transported mainly from the northern part to southern part by longshore littoral currents, and some portions of sediments are transported from the southern part to the northern part by the Gulf Stream.

• Ocean and Polar Research
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• 제32권2호
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• pp.113-122
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• 2010

Understanding the abundance and distribution of massive jellyfish is necessary to forecast where or when their blooms will happen. The acoustic technique is one of the most useful methods of obtaining information if the acoustic characteristics of the targets are known. This study was conducted to determine the acoustic target strength (TS, dB) of two jellyfish species, Aurelia aurita and Cyanea nozakii, in the southern coast of Korea. For the ex situ measurements, 120, 200, and 420 kHz split beam transducers were used, and jellyfish with various bell lengths were arranged to prepare multiple jellyfish. Under 2 vertical individuals, the mean TS for multiple A. aurita at 120, 200, and 420 kHz was -72.7, -71.7, and -68.2 dB, respectively. In the case of 5 vertical individuals, the mean TS of the species was -71.3, -68.2, and -62.0 dB. Finally, the mean TS of C. nozakii at 120, 200, and 200 kHz was -62.0, -60.3, and -58.2 dB under 2 individuals and -58.1, -57.4, and -54.0 dB under 4 individuals, respectively. For both species, higher numbers of jellyfish resulted in a higher TS. In addition, higher frequencies were associated with a higher TS for the same jellyfish. These TS results for two species can be used as essential data for the acoustic detection of jellyfish in an open ocean or coastal area.

• 한국수산과학회지
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• 제16권4호
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• pp.368-378
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• 1983

본 연구는 1982년 6월부터 1983년 5월까지 전남 여수반도 남단에 위치한 오동도 해조군락의 특성을 밟히기 위하여 5개의 line transect를 설치하고 연간 계절별로 조사된 자료를 분석 하였다. 해조류의 수직분포는 상부군이 Gelidium divaricatum, Enteromorpha linza, Porphyra yezoensis, Scytosiphon lomentaria, Blidingia nana, Ectocarpus confervoides, 중부군이 Ulva pertusa, Chondria crassicaulis, 그리고 하부군은 Sargossum sagamianum, Undaria pinnatifida, Sargassum thunbergii 및 Gelidium amansii 등의 홍조류로 대표되었다. 출현해조의 종수와 피도는 4월에 최대이고 8월에 최소로되며 종별 우점도의 변화는 연중 출현종은 10월에, 일계절 출현종은 1월 또는 4월에 각각 최대치를 나타내었다. 유사도지수에 따른 5개 transect의 cluster analysis 결과 내만성군과 외양성의 2군으로 분류되었으며 본 지역은 남해안 중${\cdot}$동부 군락에 해당되는 Myelophycus simplex alliance의 Colpomenia sinuosa-Ecklonia cava association에 속한다고 본다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 춘계학술대회 논문집
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• pp.217-224
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• 2004

개방해역에서의 폭풍고조의 계산은 특히 해안역의 계획 및 건설 작업 분야에서 의미있는 것이다. 본 연구에서 태풍으로 인한 수위의 변화예측은 물리모델에서나 실제현장에서 다루기가 매우 어렵기 때문에 수치모델에 주로 근거를 두었다. 폭풍고조에 대한 단순준이차원 수치모델을 다루었다. 모델배경에서 여러 가지 가정, 유효범위, 적용성을 이해하기 위하여 태풍과 폭풍의 발생과정을 좌우하는 물리적 인자들에 대하여 논하였다. 또한 수학적 관점 뿐만아니라 물리적인 관점에서 모델의 주요특성을 나타내기 위해 모델의 수립과정에 일반적으로 취한 가정과 함께 지배방정식을 따랐다. 본 논문에서 기술한 모델과 일치하는 방정식은 지배방정식을 축약시킨 것으로 이에 따른 수치기법을 제시하였다. 최종적으로 한국 남해안의 마산항에서 폭풍고조의 문제에 위에서 기술한 모델을 적용하여 천문조, 초기수면, 대기압에 따른 수위상승의 효과를 고려하였다. 아울러 해안도시역에서의 침수원인을 분석하고, 침수방지를 위한 합리적인 제안을 제시하였다.

• 한국환경과학회지
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• 제11권9호
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• pp.865-880
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• 2002

As prevailing synoptic scale westerly wind blowing over high steep Mt. Taegulyang in the west of Kangnung coastal city toward the Sea of Japan became downslope wind and easterly upslope wind combined with both valley wind and sea breeze(valley-sea breeze) also blew from the sea toward the top of the mountain, two different kinds of wind regimes confronted each other in the mid of eastern slope of the mountain and further downward motion of downlsope wind along the eastern slope of the mountain should be prohibited by the upslope wind. Then, the upslope wind away from the eastern slope of the mountain went up to 1700m height over the ground, becoming an easterly return flow in the upper level of the sea. Two kinds of circulations were detected with a small one in the coastal sea and a large one from the coast toward the open sea. Convective boundary layer was developed with a thickness of about 1km over the ground in the upwind side of the mountain in the west, while a thickness of thermal internal boundary layer(TIBL) form the coast along the eastern slope of the mountain was only confined to less than 200m. After sunset, under no prohibition of upslope wind, westerly downslope wind blew from the top of the mountain toward the coastal basin and the downslope wind should be intensified by both mountain wind and land breeze(mountain-land breeze) induced by nighttime radiative cooling of the ground surfaces, resulting in the formation of downslope wind storm. The wind storm caused the development of internal gravity waves with hydraulic jump motion bounding up toward the upper level of the sea in the coastal plain and relatively moderate wind on the sea.

• Ocean and Polar Research
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• 제31권1호
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• pp.111-119
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• 2009

Biogenic surface films, which are often present in coastal areas, may enhance the signatures of hydrodynamic processes in microwave, optical, and infrared imagery. We analyzed ERS-1/2 Synthetic Aperture Radar (SAR) and Envisat Advanced Synthetic Aperture Radar (ASAR) images taken over the Japan/East Sea (JES). We focused on the appearance of the contrast SAR signatures, particularly the dark features of different scales caused by various oceanic and atmospheric phenomena. Spiral eddies of different scales were detected through surface film patterns both near the coast and in the open regions of the JES in warm and cold seasons. During field experiments carried out at the Pacific Oceanological Institute (POI) Marine Station 'Cape Shults' in Peter the Great Bay, the sea surface roughness characteristics were measured during the day and night using a developed polarization spectrophotometer and various digital cameras and systems of floats. The velocity of natural and artificial slicks was estimated using video and ADCP time series of tracers deployed on the sea surface. The slopes of gravity-capillary wave power spectra varied between .4 and .5. Surface currents in the natural and artificial slicks increased with the distance from the coast, varying between 4 and 40 cm/s. The contrast of biogenic and anthropogenic slicks detected on vertical and horizontal polarization images against the background varied over a wide range. SAR images and ancillary satellite and field data were processed and analyzed using specialized GIS for marine coastal areas.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.155-161
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• 1999

The land reclamation area of Saemangeum(Kunsan) is located between 126$^{\circ}$10' E~126$^{\circ}$50' E and 35$^{\circ}$35' N~356$^{\circ}$05'N at the western coast of the Korean peninsula. The are many small islands including extensive areas of semi-diurnally flooded and dewatered tidal flats. The reclamation area of Saemangeum has a range of 5.6m spring tide and the maximum tidal current speed is about 1.41m s-1 in ordinary spring tide. Most of the sediments deposited on the tidal flats are transported from the Geum river, the Manjyung river and The Dongjin river. The soil in this area consists of silty sand with the depth of 10m to 30m . The wind in winter is strong from the direction of northwest. In the past twenty years, land reclamation projects for agricutural purpose or industrial cocmplex have been mostly implemented along the western coast of Korea. Saemangeum coastal area is being constructed the33km sea dike and 40, 100ha reclamation area. The purpose of this study is to find the residual circulations in four seasons after the dike construction by a robust diagnostic and prognostic numerical model. Heat flux at the sea surface in January ,May , August , October was asopted on the basis on the daily inflow of solar radiation at the earth surface, assuming an average atomospheric transmission and no clouds , as a function of latitude and time of year(George L.P.J.E William, 1990). The discharge from the Geum , the Mankyung and the Dongjin rivers was adopted on the basis of experience formula of river flow in January , May ,August, October (The M. of C.Korea, 1993) . Water temperature and salinity along the open boundaries are obtained from the results of field observation s.