• Journal of Korean Society of Coastal and Ocean Engineers
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• v.6 no.3
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• pp.266-274
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• 1994

Two-dimensional numerical analysis is performed for the simulation of tidal characteristics related to various development projects in Incheon coastal waters along the west coast of Korea. Field observation of tides and currents was made in order to provide the input boundary and validation data set to the numerical modelling. For the simulation of changes of tides and currents a depth-integrated two-dimensional shallow water model of Flather and Heaps (1975) has been used herein. Tidal model is set up with open boundary sea level from observed two major constituents, M$_2$ and S$_2$. Subsequently the established model is utilized to investigate the effect of two development projects in this region. It has been found that in spring tide the changes of tidal amplitude are small, however, those of tidal current are locally significant.

• Geophysics and Geophysical Exploration
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• v.14 no.2
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• pp.133-139
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• 2011

The largest terms in the solid Earth body tide calculation are second degree spherical harmonic components due to the moon or the sun, and they compose about 98 percent of total contribution. Each degree harmonics of the tidal perturbation should be evaluated through multiplication with distinct Love numbers or their combinations. Correct evaluation of these terms in gravity tide is considered with re-calculated Love numbers. Frequency dependence of Love numbers for spherical harmonic tide upon the order number is discussed. Tidal displacement and tidally induced deviation of the vertical are also evaluated. Essential concepts underlying the body tide calculation are briefly summarized.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.429-441
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• 2011

In the southeast coastal zone of Yellow Sea, the tide characteristics showing ebb-dominant tide and tidal flow were confirmed by analysis of observed tide and tidal currents. Physical factors generating asymmetric tide were reviewed. Influence of bottom shear stress, tidal flat, and nonlinear terms in shallow water equations was investigated by two-dimensional tide modeling. The model results gave good agreements with observed tides, but the amplitude of simulated $M_4$ tide was less than that of observed tide. The tidal flats existing in the study area widely have great effect on the generation of nonlinear tide. The M4 tide is mainly generated near the tidal flats. The deletion of tidal flats prevents the production of the M4 tide. We can conclude that the wide tidal flats is a primary cause of tide asymmetry in the study area.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.2
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• pp.93-100
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• 1999

Analyzing the tide data taken at Kunsan inner and Outer ports, non-tidal and mean sea level and harmonic constants of major constituents are investigated to examine the effects of the dyke gate operation on the sea level change in Keum River estuary. Non-tidal and annual mean sea levels decrease at Kunsan Inner and Outer ports after the dyke gate operation, especially showing an abrupt drop of non-tidal sea level at Kunsan Inner port. This non-tidal sea level drop results in the mean sea level gradient change between the inner and outer port, which can be mainly explained in terms of the decrease of river discharge from the dyke. Amplitudes of the $M_2$ and $S_2$ tides at the Inner port increase after the dyke gate operation, showing an abrupt jump, and phases of both tides slightly decrease. Amplitude and phase of the $K_1$ and $O_1$ tides show slight changes after the dyke gate operation. This significant change of semi diurnal tide amplitude is believed as a result of superposition of incident tidal wave and reflected tidal wave from the dyke.

• Water for future
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• v.20 no.2
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• pp.161-168
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• 1987

The prediction of changes in the tidal regime due to the construction of a barrier in the Keum River was performed via one-dimensional numerical model. It is shown that a barrier in Mangwolri will lead to a small increase in the $ tidal range. The validity of this prediction is examined using the hydrodynamic analogy with AC circuit theory. Some of preliminary results are presented and discussed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.4
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• pp.313-325
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• 2011

Finite element grid system using h-refinement on the Yellow Sea was constructed based on previous study (Suh, 1999b) from 14 K to 210 K and special attention was concentrated on refining the coastal zone. In grid generation, depth change between adjacent points and non-dimensional tidal wave length ratio were considered. As a result approximately a quarter of the total nodes are located nearby 5 m of shallow area. Accurate bathymetry data using 30's and ETOPO1 with open boundary conditions of 8 major tidal constituents extracted automatically from FES2004 have been applied. In tidal simulation a 3-dimensional nonlinear harmonic model was setup and tidal amplification due to changes in vertical turbulent and bottom friction were simulated. In this study not only 8 major tidal constituents but also nonlinear shallow tides $M_4,$, $MS_4$ and long period $M_f,$, $M_{sf}$ were reproduced. It is found that implication of spatial variation of friction coefficient plays a very important role in reproduction of astronomical and shallow tides which are computed by iterative computation of nonlinear terms. Also it should be considered differently with respect to tidal periods. To understand the distribution of tidal asymmetry, amplitude ratio of $M_4/M_2$ and phase differences $2g(M_2)-g(M_4)$ were calculated. Tidal distortion ratio marks up to 0.2 on the west coast showing shallow coastal characteristics and somewhat wide range of ebb-dominances in front of Mokpo area are reproduced.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.2
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• pp.81-91
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• 2016

Harmonic analysis of tide data observed on the western coasts has been conducted. The changing trends of harmonic constants were reviewed. Overall, amplitudes of semidiurnal tide are not changed and present phases are faster than in the past. In Mokpo located in a semi-enclosed bay, the amplitudes have been greatly increased and the phases have become earlier due to construction of sea-dike and seawalls. Harmonic constants of diurnal tide have not been changed except Mokpo. In Mokpo the phases of diurnal tide have been earlier. Tidal ranges in spring tide and neap tide have not been significantly changed except Mokpo. In Mokpo tidal ranges have been increased and tidal flats widened. Approximate higher high water has been overall rising. Therefore, Korean western coasts can be easily inundated than before.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.1
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• pp.33-41
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• 1999

Time-lag and amplitudes of the fluctuation of groundwater level are used to determine hydraulic parameters around Han River. The groundwater level at observation wells fluctuates between highest and lowest responding to the Han River level. The factors affecting the groundwater fluctuation are examined. The transmisivity of the Han River alluvium calculated from the measured water table fluctuations measured ranges from 9.39${\times}$10$^1$to 4.02${\times}$10$^3$㎡/day. Based on the hydrogeological data along the river sides, the flow characteristics of groundwater for water level fluctuations were simulated using a ground water flow model MODFLOW.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.104-104
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• 2021

연안에 발생하는 지진해일은 많은 인명 및 재산 피해를 유발할 수 있다. 이에 따라 주요 선진국은 자국의 피해 뿐 아니라 세계 주요도시에 거주하는 자국민의 안전과 대피에 대한 경보발령을 목적으로 전지구 지진해일 시스템을 구축하여 상시 운영중에 있다. 우리나라의 지진해일 예측시스템은 지진해일의 발생과 전파, 그리고 전세계 주요 연안에 도달할 때의 해일고 모의 등에서 우수한 성과를 보이는 것으로 인정되고 있으나, 실제적인 위험경보를 발령하기 위해서 필요한 해일도달 시 조위와의 상호작용에 대한 기능은 현재 없는 상태이다. 해일에 의한 주된 피해는 연안으로의 범람에 대한 것으로 이를 파악하기 위해서는 해일 도달 당시의 조위를 예측하고 해일과 조석과의 상호작용을 반영한 예측시스템 구축이 필요하다. 이에 따라 본 연구에서는 현재 사용되고 있는 지진해일 예측모델에서 조석-지진해일 상호작용을 고려하기 위해 조석과 지진해일을 동시에 모의할 수 있는 예측 알고리즘을 제시한다. 지진해일의 전파 및 범람에 조석이 상당한 영향을 미칠 수 있음은 관련 연구자들에 의해 꾸준히 지적되어왔으나 과거 연구는 이상적인 지형이나 조석 조건에 대해서만 일부 이루어졌으며, 아직까지 실제 조석을 활용한 충분한 연구는 미흡한 실정이다. 향후 실제 조석에 의한 지진해일의 변화를 모의하기 위해 지진해일 예측모델에서 실제 조석과 조류 조건에서 지진해일을 동시에 모의할 수 있도록 예측 알고리즘을 개발하였다.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.637-650
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• 2002

This study presents an investigation of the changes of the currents in Kwangyang Bay due to the construction of harbor, reclamation and coastal developments. Currents were simulated by the numerical experiments with a diagnostic multi-level model and using the seasonal oceanographic data of temperature, salinity and ocean current. The values of kinetic and potential energies for the currents were calculated in cases of three topographical changes; before coastal developments, the existing state and after completion of the development project in Kwangyang Bay. The changes of currents due to the coastal developments are as follow; Kinetic energies of tide induced residual currents and wind driven currents decreased by 35~40 percent and 5 percent respectively, however those of density currents increased by 10 percent since the decrease of the coastal areas. Kinetic energy of residual currents including tide induced residual currents, density currents and wind driven currents reduced by 10 percent compared with before the coastal developments. Decrease of current velocity was greatest in summer. Therefore, in summer it was assumed that the Kwangyang Bay is more easily polluted by stratification and decrease of residual current than before the coastal developments carried out.