• Journal of Environmental Science International
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• v.20 no.2
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• pp.275-289
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• 2011

In order to clarify the relation between sea breeze penetration and Planetary Boundary Layer development in southeastern part of the Korean Peninsula, several numerical assessments were carried out using atmospheric numerical model WRF(Weather Research and Forecasting). Compared with onset time of sea breeze at eastern coast area(Uljin), the time at southern coast region(Masan) with complex costal line tend to delay for several hours. The penetration patterns of sea breeze between two coastal regions are some different due to the shape of their coastal line and back ground topography. Intensified valley wind due to high topography of lee side of Uljin can help penetration of sea breeze at early time. So penetration of sea breeze at early time often prevent PBL to develop at Uljin and lower PBL height last for a day time. But because of late penetration of sea breeze at Masna, PBL Height dramatically decrease after 1500LST. The distribution of front genesis function based on the heat and momentum variation are explained obviously the sea breeze penetration patterns and agreed well with the PBL height distribution.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.3
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• pp.146-157
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• 2019

Recently, the importance of highly accurate bathymetric data is greatly emphasized by the increased use of the ocean numerical models and research results in major areas such as ocean forecasting and natural disaster. There are domestic bathymetric data mainly used in ocean numerical models of Choi et al.(2002) and Seo (2008), but the production year is old and the data was created on the basis of nautical charts. Nautical charts are made for the purpose of navigation and based on the minimum depth from bathymetric data, so there is a limitation to reproduce the actual submarine topography. Korea Hydrographic and Oceanographic Agency (KHOA) produces nautical charts every year through continuous bathymetric survey, but no bathymetric data for numerical models have been produced. In this study, using the raw bathymetric survey data, we built an exclusive bathymetric dataset (BADA Ver.1) for ocean numerical models and compared it with published bathymetric data.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.1
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• pp.57-65
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• 2007

Shallow water waves are hindcasted from sea wind fields, which include wave transformations such as shoaling, refraction, diffraction, reflection and wave breaking. In case of estimating sea wind field in shallow water, the sea wind revised from free wind obtained by the typhoon model is widely used. However, this method is not able to consider the effect of land topography on the wind field, which will be important factor for shallow water wave forecasting and hindcasting. In this study, therefore, the effect of land topography on sea wind field in shallow water is investigated for shallow water wave forecasting and hindcasting with high accuracy. The 3-D MASCON model is introduced to consider the influence of land topography on the wind field. And, for two areas divided by the topographical characteristics, i.e. shielded and opened coastal areas, sea wind field is examined by comparison between initial wind field by typhoon model and modified wind field by 3-D MASCON model. Finally, applying these sea wind fields to SWAN model, the results of shallow water wave calculated in shielded and opened coastal areas are compared, and, also, the effect of MASCON model on shallow water wave forecasting and hindcasting is discussed.

• Journal of Environmental Science International
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• v.20 no.6
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• pp.679-686
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• 2011

The characteristics of circulation in the coastal area of Jeju Harbor in Korea was examined using the Princeton Ocean Model(POM) with a sigma coordinate system. The result of numerical analysis well corresponded to the observed current data. The velocity at offshore was stronger compared to coastal area during the both period of in maximum flood and maximum ebb of spring tide. According to mean wind velocity, the tidal velocity at the shallow area of Jocheon was slightly increasing during maximum ebb. The effect of wind on the circulation was stronger in shallow area and showed rapid change with depth.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.2
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• pp.91-107
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• 2009

In order to compute linear wave transformation over a single step bottom, both variational approximation and eigenfunction expansion method are used. Both numerical results are in good agreement for reflection and transmission coefficients, surface displacement respectively. However x velocity profiles at the boundary of step are seen to be different to each other even though x velocity matching condition is used.

• Journal of Environmental Science International
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• v.8 no.5
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• pp.555-558
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• 1999

A sea/land breeze circulation system and a regional scale circulation system are formed at a region which has complex terrain around coastal area and affect to the dispersion and advection of air pollutants. Therefore, it is important that atmospheric circulation model should be well designed for the simulation of regional dispersion of air pollutants. For this, Local Circulation Model, LCM which has an ability of high resolution is used. To verify the propriety of a LCM, we compared the simulation result of LCM with an exact solution of a linear theory over a simple topography. Since they presented almost the same value and pattern of a vertical velocity at the level of 1 km, we had a reliance of a LCM. For the prediction of dispersion and advection of air pollutants, the wind filed should be calculated with high accuracy. A numerical simulation using LCM will provide more accurate results over a complex terrain around coastal area.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.6
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• pp.553-563
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• 2008

If an arbitrary topography is approximated to a number of vertical steps, both variational approximation and eigenfunction expansion method can be used to compute linear wave transformation over the bottom. In this study a scatterer method associated with variational approximation is proposed to calculate reflection and transmission coefficients. Present method may be shown to be more simple and direct than the successive-application-matrix method by O'Hare and Davies. And Several numerical examples are given which are in good agreement with existing results.

• Korean Journal of Remote Sensing
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• v.17 no.2
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• pp.121-129
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• 2001

A DEM(digital elevation model) is generated from a SPOT panchromatic stereo-pair using automated algorithms over a 8 km$\times$10 km region around Mokpo city. The aims are to continue the accuracy assessment over diverse conditions and to examine the applicability of a SPOT DEM for coastal disaster monitoring. The accuracy is assessed with respect to three reference data sets: 10 global positioning system records, 19 leveling data, and 1:50,000 topography map. The planimetric error is 10.6m r.m.s. and the elevation erroer ranges from 12.4m to 14.4m r.m.s.. The DEM accuracy of the flat Mokpo region is consistent with that over a mountainous area, which supports the robustness of the algorithms. It was found that coordinate transformation errors are significant at a few meters when using the data from leveling and topographic maps. The error budget is greater than the requirements for coastal disaster monitoring. Exploiting that a sub-scene is used, the affine transformation improves the accuracy by 50% during the camera modeling.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.2
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• pp.59-62
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• 1992

Empirical criteria for wave breaking on the coastal slope are substantiated theoretically for complex-shape basins. The theory developed here is a generalization of Carrier-Greenspan theory for a plane beach. The place and role of the linear theory for the description of run-up problem is discussed. The height of run-up on the beach of the basins with a “parabolic” profile is calculated for originally monochromatic wave.

• Journal of Korean Port Research
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• v.12 no.1
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• pp.105-111
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• 1998

A horizontal 2-D model which includes the wetting-drying treatment technique in the intertidal zone is applied for the prediction of tidal changes. The flow model is applied to Mokpo coastal zone and verified by measurement data. Comparing computation results with observed values for the M2 tidal constituent, agreeable correspondence is detected. The validity of the model is also proven by applying it to such areas which have narrow width and rapid velocity, irregular topography and complex geometry. Thus, this model can be used as the compatible prediction model for the tidal change and pollutant transport due to the development of Mokpo coastal zone.