• 한국지형학회지
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• 제26권4호
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• pp.67-79
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• 2019

This study documents the level of paleo-shoreline and the timing of formation of the lowest marine terrace (1st terrace) distributed in Dadaepo, Busan, South Korea. In the study area, the elevation of paleo-shoreline of the 1st terrace is clearly identified as 5 meters above mean high tide based on the elevation of wave-cut platforms and the elevation of boundary between marine and terrestial sediments. This is well consistent with the fact that are found along the Southern coast of the Korean Peninsula including Daepo-dong, Sacheon-si. The timing of formation of the 1st terrace in Dadaepo is confirmed to have been deposited around 70,000~80,000 years BP (MIS 5a) according to OSL and IRSL dating ages. However, because the formation age of the 1st terrace in Sacheon-si Daepo-dong (Southerm coast) and Pohang-si Umok-ri (Eastern coast) previously identified as about 90,000~100,000 years BP (MIS 5c), further discussion of what is needed. Possibly, it can be interpreted that the sub-interglacial (MIS 5a and 5c) sea-level records during the last interglacial period are likely to be selective on land depending on regions.

• 한국해안해양공학회지
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• 제7권3호
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• pp.265-276
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• 1995

본 논문에서는 실시간 해황예보 시스템 개발의 일환으로 수행된 회선적분법을 이용한 신속 표층유속 재현에 대하여 다룬다. 바람응력은 공간적으로 균일하고 대 기압은 무시된다. Data Base 구축을 위하여 4방향의 바람(북서, 북동, 남서, 남동)을 고려하여 각 지점의 회선적분의 가중치를 Galerkin-FEM 모형에 의해 계산하였다. 시간에 따른 바람응력이 주어지면 구성된 Data Base를 이용하여 회선적분법에 의해 신속한 예보가 가능하다. 시간적으로 변하는 임의의 바람응력은 6시간 단위로 정의되는 wind pulse의 연속으로 표현되며 총 12개의 pulse(즉, 72시간전)가 convolution product에 사용된다. 회선적분법의 적용 가능성을 확인하기 위하여 황해 이상화한 해역과 황해와 동지나해에 이르는 실제 해역에서의 수치실험이 수행되었다. 고려한 바람응력은 역풍류 생성 확인을 위하여 시간에 따라 sin 함수적으로 변하는 북풍을 고려하였고, 실험 결과 역풍류 생성의 화인과 회선적분법을 이용한 신속 표층해류 예측 가능성을 확인할 수 있었다.

• 한국지리정보학회지
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• 제22권1호
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• pp.51-61
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• 2019

한반도 주변 연안의 수준기점에서 해면경사를 계산하는 것은 우리나라 측지수준망의 수준기점 표고를 설정하는데 중요하다. 본 연구에서는 국제수로기구 기준(18.6년)으로 장기 조위관측 자료의 평균해수면을 재계산하고, 수준측량으로 수준기점의 표고를 재 분석하였다. 그리고 목포, 부산, 묵호 수준기점에서 수준측량에 의한 해면지형 분석방법으로 인천 수준원점을 기준으로 한 해면경사를 계산하였다. 그간 국내 측지학자와 해양학자들은 남북 위도상의 해면경사 문제에 대하여 서로 상반된 견해를 보였다. 본 연구결과 북위 $37.5^{\circ}$에 위치한 인천(-2.27cm)과 묵호(17.56cm) 간의 동 서 해면경사는 19.83cm으로 분석되었다. 또한 목포의 평균해수면이 인천 보다 1.12cm 높고, 부산의 평균해수면이 묵호 보다 2.18cm 높은 해면경사가 남향 상승하는 것으로 분석되었다. 본 연구결과 서해안과 동해안은 남향 상승하는 해면경사 분석 결과는 우리나라 측지수준망의 재설정과 수준망에서의 표고차 불일치 문제를 해결하는데 활용될 수 있을 것이다.

• 한국지형학회지
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• 제17권1호
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• pp.1-14
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• 2010

본 논문은 비접근지역인 DMZ에서 동해안의 원산만에 이르는 추가령 열곡에 대해 GIS를 이용하여 지형면을 분류하고 그 분포의 특징과 형성과정에 미친 영향을 분석한 것이다. 분석 방법으로 수치고도모델(DEM)과 Landsat 위성영상을 이용하였다. 지형면 분류는 고도, 경사도, 기복량 등을 이용하여 지형 표면의 요철 정도를 지수로 산출하는 TPI(Topographical Position Index)를 이용하였다. 연구지역의 지형면은 깊은 계곡, 얕은 계곡, 산지유로, 평탄곡지, 평탄지(단구, 평야, 대지), 산록사면, 산복사면, 소구릉, 완사능선, 산정능선 등 10가지 유형으로 분류하였다. 이들 지형면의 지형형성과정의 평균적인 특성을 파악하기 위하여 기반암과 기복량, 지형면과 기복량, 지형면과 식생활력도 등의 관계에 대한 구역 평균(Zonal Statistics)을 실시하였다. 이러한 분석을 통하여 비접근 지역인 추가령열곡 DMZ의 용암대지 개석과정과 분수계 발달과정 등을 파악할 수 있었다.

• 한국해안·해양공학회논문집
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• 제22권2호
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• pp.67-72
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• 2010

본 연구에서는 조류발전용 헬리컬 수차를 발전소 냉각수 배수로에서의 수력 개발에 이용하기 위하여 수차구조물의 설치로 인한 수위 증가가 냉각수 순환 계통에 미치는 영향을 파악하였다. 배수로 암거 출구부에 가로 3.6 m $\times$ 세로 1.5 m의 헬리컬 수차 1 set(2기 일체형)를 설치하는 경우에 대하여 배수로의 수위변화 및 압력변화를 수치해석을 통해 분석한 결과, 평균해수위시에는 seal well 하류의 수위 변화 영향이 seal well의 weir에 의해 차단되어 상류로 전파되지 않았다. 그러나 고조시에는 weir의 월류 흐름형태가 잠김 월류가 되고 seal well 전 후단이 모두 만관흐름상태가 되어 하류의 압력변화가 상류로 전파되었다. 방류 개시 후 약 10분간 불안정한 압력변화가 발생하나 이후 안정되며, 약 0.2 m 내외의 수두 증가로 냉각수 순환펌프 소요 동력이 증가할 수 있으나 안전성에는 영향을 주지 않을 것으로 판단되었다. 따라서, 수력 개발 타당성 평가시 냉각수 순환펌프의 소요전력 증가를 고려할 필요가 있다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.297-300
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• 2008

High-resolution mesoscale meteorological modeling requires more accurate and higher resolution digital elevation model (DEM) data. Shuttle Radar Topographic Mission (SRTM) has created 90 m DEM for entire globe and that is freely available for meteorological modeling and environmental applications. In this research, the effects of the topographic interpolation methods on high-resolution wind field simulation in the coastal regions were quantitatively analyzed using Weather Research and Forecasting (WRF) model with SRTM data. Sensitivity experiments with three different interpolation schemes (four-point bilinear, sixteen-point overlapping parabolic and nearest neighbor interpolation methods) were preformed using SRTM. In WRF modeling with sixteen-point overlapping parabolic interpolation, the coastal line and some small islands show more clearly than other cases. The maximum height of inland is around 140 meters higher, while the minimum of sea height is about 80 meter lower. As it concerns the results of each scheme it seems that the sixteen-point overlapping parabolic scheme indicates the well agreement with observed surface wind data. Consequently, topographic changes due to interpolation methods can lead to the significant influence on mesoscale wind field simulation of WRF modeling.

• 한국농공학회논문집
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• 제57권6호
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• pp.1-7
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• 2015

Most of chloride diffusion models based on finite difference method (FDM) could not express the diffusion in horizontal direction at each elevation. To overcome these weakness, two dimensional chloride ion penetration model based on finite element method (FEM) to be able to combine various multi-physics simultaneously was suggested by introducing moving mesh technique. To avoid the generation of mesh being able to be distorted depending on the relative movement of water level to static concrete, a rectangular type of mesh was intentionally adopted and the total number of meshes was empirically selected. The simulated results showed that the contents of surface chloride decreased following to the increase of elevation in the top part of low sea level, whereas there were no changes in the bottom part of low level. In the DuraCrete model, the diffusion coefficient of splashed zone is generally smaller than submerged zone, whereas the trend of Life365 model is reverse. Therefore, it could be understood that the developed model using moving mesh technique effectively reflects $DuraCrete^{TM}$ model rather than $Life365^{TM}$ model. In the future, the model will be easily expanded to be combined with various multi-physics models considering water evaporation, heat of hydration, irradiation effect of sun and so on because it is based on FEM.

• Ocean and Polar Research
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• 제25권spc3호
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• pp.423-426
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• 2003

The seawater exchange breakwater equipped with an oscillating water channel and water transmitting pipes has a very spectacular function that seawater supply can be greatly increased due to the upsurge of the water surface inside the channel at resonance condition which can be reached when the incident wave period becomes close to the natural period of the channel. The variations of the water level and period inside the channel are very important factors in enhancing the efficiency of sea water exchange, especially when designing the breakwater cross-section in shallow water zone which requires longer resonance period with the elongated horizontal projection of the channel. In the present study, a hydraulic experiment was performed varying the length of the oscillating channel, and the resonance periods and water surface variations are analyzed in terms of water transmission through the pipes.

• 한국환경과학회지
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• 제19권12호
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• pp.1361-1374
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• 2010

The impact of urbanization on local meteorology (e.g., surface temperature, PBL height, wind speed, etc.) in the Greater Seoul Area (GSA) was quantitatively evaluated based on a numerical modeling approach during a 1-month period of 2001 (9 Sep. through 8 Oct. 2001). The analysis was carried out by two sets of simulation scenarios: (1) with the global land use and topographic data from the U.S. Geological Survey (USGS) in 1990s (i.e., LU-USGS case) and (2) with the land use data from the Environmental Geographic Information System (EGIS) along with the 3 sec elevation data from the Shuttle Radar Topography Mission (SRTM) in 2000s (i.e., LU-EGIS case). The extension of urban areas in the GSA (especially, the southern parts of Seoul) accounted for 1.8% in the LU-USGS case and 6.2% in the LU-EGIS case. For the simulations, the surface temperature and PBL height due to urbanization in the LU-EGIS case was higher (the differences of up to $0.1^{\circ}C$ and 36 m, respectively) than those in the LU-USGS case, whereas the wind speed (up to 0.3 $ms^{-1}$) in the former was lower than that in the latter at 1500 LST. The increase in surface temperature due to urbanization in the GSA (especially, the southern parts of Seoul) was led to the strong convergence of air masses, causing the early sea breeze and its rapid propagation to inland locations. In addition, the vertical mixing motion in the extended urban areas for the LU-EGIS case was predicted to be stronger than that for the LU-USGS case and vice versa for the original urban areas.

• 한국환경복원기술학회지
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• 제2권3호
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• pp.1-9
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• 1999

This paper described the results of the characteristics of the near-bottom flow and field analysis of the tidal flats sediment. It was the aim of this paper to grasp current flow of tidal flat's environment and influence factor for environmental change forecast of tidal flats. Field measurement of water velocity, water elevation, bed materials test, and temperature distribution of tidal flat were conducted. Thereafter, current flow, turbidity and temperature distribution of tidal flat sediment have been discussed. The field research results showed that the fluctuating velocity near the seabed before and after its appearance at low tide was strongly affected by the wind wave. The resuspension of the sea-bottom sediment took place with great intensity before and after the appearance of the seabed at low tide. Both the sea water level and the weather condition were a significant influential factors. Such as, temperature and turbidity just on the surface and the shallow layer of seabed sediments were varied largely with time and weather conditions, but that its deeper layers was almost constant. Temperature on the seabed sediments was strongly influenced by irradiance and water depth. The temperature variation of the tidal flat and the variation characteristics of the current flow and turbidity depend greatly on the inhabiting environment of the tidal flat benthic organism.