• Ocean and Polar Research
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• v.30 no.1
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• pp.33-46
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• 2008

In order to investigate seasonal variations of the physical environments in the region of Jinhae Bay-Nakdongpo, we carried out hydrographic surveys from November 2000 to November 2001. Horizontal and vertical distribution of salinity and temperature shows large seasonal variations. Water column is well mixed in winter and stratified in summer. Low-salinity water is distributed in the form of patches because of the drainage control at the Nakdong River. Seasonal variations in the sea near Gadeok-Sudo are affected by topography, river discharge and tidal current. Currents have been measured using a bottom mounted ADCP and DCM12 between November 2000 and August 2001 in the Gadeok-Sudo. The current in the Gadeok-Sudo shows a distinct two-layer structure with reversed current. Low-pass filtered time series of wind, sea elevation and current are coherent for the period of 1-2 days and are attributed to Ekman-like dynamics. Spatial and temporal circulation pattern shows a slight different. The subtidal current in Jinhae Bay goes northward, however is reversed in the Gadeok-Sudo mouth.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.2
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• pp.79-85
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• 1989

The generation and propagation of shelf wave-like oscillations induced by local wind at a basin with continental shelf and slope are studied by a numerical experiment. Three types of vortices are generated along western boundary and they propagate along the boundaries in the counter-clockwise direction. The first vortex is generated at the early stage of wind stress and its center is located off the continental slope. The second type centered on the continetal slope is generated at about the terminating time of wind stress and follows the first one. The third, centered on continental shelf, decays so soon that its propagation pattern is hard to be identified. Each of those vortices is probably to be one of free modes of the model basin.

• Journal of the korean society of oceanography
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• v.37 no.3
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• pp.134-143
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• 2002

Using OGCM results, we have shown that the ring-like cold baroclinic eddies associated with cyclonic circulation are shed from late summer to early fall near the Izu-Ogasawara Ridge from the Kuroshio Extension owing to baroclinic instability. On the other hand, warm baroclinic eddies are generated by the intensified western boundary current associated with the warm anomaly accumulated near the Ridge in winter, which corresponds to the basin-wide barotropic intensification of the wind-driven gyre in winter. We are successful in reproducing the behavior of those meso-scale eddies using a simple two-layer primitive equation model driven by seasonal winds associated with the positive curl. Those eddies carry barotropic seasonal signals originated in the Pacific Basin quite slowly west of the ridge; this process introduces a phase lag in the timing of the seasonal maximum transport in the Philippine Basin west of the ridge. It Is demonstrated that the existence of bottom topography, baroclinicity, and nonlinearity due to advection are three necessary elements for the generation of these eddies south of Japan.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.2 no.2
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• pp.67-74
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• 1990

A numerical model is developed to predict the shoreline change by the coastal structures constructed. In order to describe the wave deformation at the shadow zone of the structure, the present model employs the mild-slope equation in steady state and the wave ray method using the coefficients of wave refraction, diffraction and shoaling. In the model results of shoreline changes for the various structures. it showed a qualitative agreement with the findings observed in the field such as tombolo, and the response of this model was found to be very sensitive to the longshore distribution of wave heights. It was also applied to a field area. From the results of the application this model is proved to be useful around the complex coastal structures and bottom topography.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.6
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• pp.477-483
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• 1987

We constructed the tidal chart of $M_2$ tide in the East Sea (Japan Sea) by an objective method. The sea level elevations at coastal stations are specified as Dirichlet boundary conditions, and the tidal constants inside of the East Sea basin are determined by the solution of the complex partial differential equation for the sea surface elevation. We studied the influences of the bottom topography and the tidal friction on the distribution of tidal chart inside of the basin. Using the results of basin-wide tidal model, we constructed a detailed tidal chart of the Ma tide off east of Korea.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.1
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• pp.36-44
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• 2006

Cohesive sediment transport in coastal region has been studied by numerical modeling. A finite element numerical model was setup to simulate hydrodynamics and sediment transport in the coastal region with complex topography. Only physical features of observed sediments has been used to determine erosion rates of bottom sediments together with the previous research results. The simulation results using the simply determined equation of erosion rates were compared with time variations of the observed SS concentration and showed good agreements. In conclusion, this method can be used to estimate transport of cohesive sediment conveniently.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.4
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• pp.323-333
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• 1990

We studied the existence, form, size, variation and formation of warm lenses in the East Sea(Japan Sea) during $1979\~1988$ based on annual reports of oceanographic observations published by the National Fisheries Research and Development Agency of Korea and data of the Hydrographic Office of Republic of Korea. The warm lenses were formed in August, 1981, 1982, 1986 during study periods. The ranges of warm lenses were 50, 60, 90 km in the east-west(EW) direction and 100, 150, 120 km in the north-south(NS) direction in 1981, 1982, 1986, respectively. Because of the intrusion of cold water near 103 line, they shrink in horizontal scale in 1981. Most warm lenses were found at station 8 of 104 line in the vicinity of Ullung Island but centers of the lenses moved to the north in 1986. The form and position of warm lenses were related with the intensity of the Tsushima Warm Current and the formation of warm lenses were related with the bottom topography.

• Journal of Environmental Science International
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• v.20 no.11
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• pp.1403-1415
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• 2011

To understand the transport of anchovy egg-larvae, an integrated model consisting of a hydrodynamic model and a three-dimensional Lagrangian diffusion model was used for the anchovy Engraulis japornicus egg-larvae trace. Fist, in order to determine the circulation characteristics of the South Sea of Korea, residual flow according to tide, density and wind effect was investigated. In offshore regions, tide-induced residual current tends to flow eastward during the spring tide and westward during the neap tide. Residual flow is irregular due to the bottom topography in the coastal area. No special tendency was apparent in the open sea. Especially, the flow in the offshore regions showed results similar to that of the Tsushima Warm Current. The transport of anchovy egg-larvae is decided the physical properties of sea water. It is estimated that anchovy eggs spawned near the Jeju Island travels offshore, rather than to coastal areas, and grow in the front area between the coastal sea and offshore regions.

• Journal of Korean Port Research
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• v.13 no.2
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• pp.409-418
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• 1999

Gamcheon Bay has complicated and unique flow pattern which is affected by topography characteristics of a semi-closed bay and warm water discharge from the power plant located at the bay. It is very important to consider warm water discharge with tidal period and wind effects, which are mainly acting on the surface flow patterns in Gamcheon Bay. The results of observation show as follows; i) Because Gamcheon bay has much elongated shape to the north-south direction and narrow entrance with two separated breakwaters, the flow is very weak inside the bay. ii) The main flow path is at the west side of the bay. The direction of flood current is northward along the west side of the bay and the direction of ebb current is southward along the west side of the bay. The southward direction of warm water discharge has curved to the west side of the bay. iii)At the period of flood current for neap tide, the flow direction is southward in the bay, which is thought by the effects of warm water discharge. But at the bottom layer, the effects of tidal current reached to the middle of the bay, and showed features like eddy. iv) The wind effect is very strong, especially, prominent in the west and east side of the bay.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.5
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• pp.366-371
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• 2012

High swell has been known for the one of the main causes of beach erosion in the east coast of Korea. In this study, coastal topography changes due to high swells are simulated to find its effect on the backshore by using movable bed experiments and numerical experiments. Sea bottom topographical changes due to various incident waves were investigated using CSHORE model in the numerical experiments. Furthermore, the mechanism and the phenomena of beach erosion due to waves and high swells on the foreshore and backshore were analyzed and compared with movable bed hydraulic experiments.