• 한국환경과학회지
• /
• 제23권2호
• /
• pp.323-330
• /
• 2014

Transport of bed load and suspended particle in coastal waters is main factor causing change in shoreline, and effective measurement method and appropriate equipment is required. To measure bed load and suspended particle transport an equipment was designed and manufactured, and it was applied in the field. The equipment consists of four main elements, body supporter, bed load and suspended particle sampler, sampler support and lock. Eight samplers were installed along the circumference of each supporter, and each sample is a 45-degree intervals. The field experiment was done once along Gyeongpo beach in August 2013. This note described the design and function of the equipment and results of field experiments.

• 한국환경과학회지
• /
• 제23권11호
• /
• pp.1801-1805
• /
• 2014

Longshore current is main transportation mean causing movement of bed load and suspended particle in coastal waters, and effective measurement method and suitable equipment for shallow water coastal environment where is frequently exposed to atmosphere. Measurement equipment for longshore drift was designed and miniature model was applied to Gyeongpo beach in May and June, 2014. The equipment consists of three main elements, spheroid outer casing, spheroid inner casing, observation module equipped with GPS. Gyroscope principle was applied to observation module, and GPS receiver always can be directed upwards. Miniature models were installed along Gyeonpo beach, and it was well to track the flow of longshore current. This research described the design and function of the equipment and results of field experiments.

• Water Engineering Research
• /
• 제1권3호
• /
• pp.187-197
• /
• 2000

This paper describes an adaptive quadtree-based 2DH wave-current interaction model which is able to predict wave breaking, shoaling, refraction, diffraction, wave-current interaction, set-up and set-down, mixing processes (turbulent diffusion), bottom frictional effects, and movement of the land-water interface at the shoreline. The wave period-and depth-averaged governing equations are discretised explictly by means of an Adams-Bashforth second-order finite difference technaique on adaptive hierarchical staggered quadtree grids. Grid adaptation is achieved through seeding points distributed according to flow criteria(e.g. local current gradients). Results are presented for nearshore circulation at a sinusoidal beach. Enrichment permits refined modelling of important localised flow features.

• 한국환경과학회지
• /
• 제6권3호
• /
• pp.239-247
• /
• 1997

The numerical experiments using a particle tracking model have been performed for predicting the change of water Quality and shoreline. In present study, comparison of the numerical model results with the analytic solution shows that the point of the mainmum concentration and the distribution pattern is very similar. The reflection effect from the boundary was newly Introduced for making clear the effect of the closed boundary which set limits to application of a particle tracking model. The present model seems to reappear physical phenomenon well. This model shows well qualitative appearance of pollutant diffusion in Kwangan beach. Therefore, this model is regarded as a useful means for predicting diffusion movement of suspended sand, and change of water quality.

• 한국해양공학회지
• /
• 제1권2호
• /
• pp.60-66
• /
• 1987

The object of this study is to investigate behaviors of beach fill replenished at three coasts of different configurations by analyzing successively measured beach profiles. The main results obtained in this study are summarized as follows; 1) The amount of nourishing sand moved in the longshore direction surpasses the amount of nourishing sand transported in the cross-shore direction regardless of shapes of the coasts and types of the structures. 2) A clear correlation between displacements of shoreline and changes of sectional areas can be found soon after the placement of beach fill in the fields. This implies that the deformation of the artificial nourishment and dissipation or remaining rate of nourishing sand can be predicated by the one-line theory. 3) The patterns of sediment movements in the artificially nourished beaches are clearly found by the analysis of empirical eignfuncitions.

• 대한지리학회지
• /
• 제50권5호
• /
• pp.473-483
• /
• 2015

본 연구에서는 소형 무인항공기를 이용하여 해안 지형을 항공촬영 한 연구결과를 바탕으로 해안선 추출 및 변화량을 분석하였다. 해안지역의 경우 해양-육지간의 지속적인 상호작용으로 변화속도가 매우 빠르고, 연구자의 직접적인 관찰이 제한되는 경우가 많아 원격탐사 자료를 이용한 많은 연구가 이루어져 왔다. 그러나 전통적인 원격탐사 방법은 시공간의 제약, 높은 운용비용 등이 한계점으로 지적되어 왔다. 이에 새로운 원격탐사 플랫폼인 무인항공기를 이용하여 해안선을 추출하였다. 촬영된 영상으로부터 이미지 프로세싱을 통해 해안선을 추출하였고, 조위차에 따른 해안선의 변화를 관찰하였다. 본 연구에서 활용한 소형 무인항공기와 소형 디지털 카메라는 기존 원격탐사 플랫폼과 비교하여 경제성에서 장점이 있다. 최근 무인항공기는 여러 분야에서 다양한 목적으로 연구가 진행되고 있는 바, 지리학 분야에서도 공간정보 구축의 플랫폼으로서 지역연구 등 다양한 활용이 가능할 것으로 판단된다.

• Ocean and Polar Research
• /
• 제36권2호
• /
• pp.87-101
• /
• 2014

Recently, more attention has been paid to the geomorphological changes in the Nakdong River Estuary, because those changes are caused by artificial activities including weirs, reclamation and construction. In order to analyze quantitatively the recent geomorphological variability in the Nakdong River Estuary, we surveyed the depth and elevation of submarine topography near Jinwoodo and Sinjado from March 2007 to February 2012. A statistical method (based on Digital Shoreline Analysis System) and an Empirical Orthogonal Functions method were used to evaluate the morphological changes. According to the statistical variables (DCE, NDC, EPR, LRR), the highest amount and rate of accumulation were recorded around the Gadeokdo whereas the greatest amount of erosion appeared around the coast off the eastern part of Sinjado. In particular, a dynamic variation of morphology was clearly observed in the vicinity of the sub-tidal channel located between Jinwoodo and Sinjado, which seems to be attributable to channel migration. As a result of the EOF method, the first mode (48.7%) is most closely related to the pattern of morphological variability that might be associated with the westerly movement of sediment by longshore current. The spatial variability of the second mode (16.6%) was high in the shoreface of Sinjado, showing a 4-year periodicity of temporal variability. The strong correlation (coefficient 0.73) between the time coefficient and suspended sediment discharge from Nakdong River emphasizes the role of sediment discharge to deposition in this area. The spatial variability of the third mode (11.3%) was distributed mainly around the coast off the eastern part of Sinjado, which is related to the movement of the coastline of Sinjado. Based on the last 5 year's data, our results suggest that the study area is characterized on the whole by a depositional pattern, but the extent of sedimentation is different locally.

• Animal cells and systems
• /
• 제3권2호
• /
• pp.161-165
• /
• 1999

Nephila clavata, a golden orb-web spider, was studied at two different field sites with respect to web size, height, and orientation. A majority of spiders at Site 1 (a band of shrub bush) built their webs parallel or nearly parallel to the edge of the bush. Similarly, at Site 2 (near a pond), most webs were aligned with the shoreline of the pond. Among the possible determining factors for the observed patterns of web orientation, wind and light did not appear important. Instead, the movement direction of insect prey appeared largely responsible. Disproportionately more webs faced outside the bush and toward the pond than inside the bush and away from the pond at Site 1 and 2, respectively. Such trend was more apparent for larger spiders with larger webs.

• 한국해안해양공학회지
• /
• 제13권1호
• /
• pp.1-8
• /
• 2001

파랑으로 인해 발생되는 흐름은 연안에서 질량수송의 일련의 과정을 야기시키므로 연안유역의 관리에 파랑과 흐름의 상호작용에 대한 정확한 이해가 요구된다. 본 논문은 적응가능한 사면 구조 격자에 근간을 둔 파랑장과 흐름장을 혼합한 수치모델을 기술하였다. 사용한 모델은 쇄파, 천수, 굴절, 회절, 파랑과 흐름의 상호작용, 평균해면의 저하와 상승, 혼합 과정, 바닥 마찰 효과 그리고 해안선에 접한 운동 등을 해석할 수 있다. 주기와 수심으로 평균한 지배 방정식은 단계적으로 엇갈린 사면구조 격자에 적응 가능한 Adam-Bashforth 2차 유한 차분 기법으로 양해적으로 모델화 되었다. 본 모델로부터의 결과는 평면 해변에서 경사 입사파에 의해 발생된 연안류의 실험치와 타당한 일치를 보였다.

• 해양환경안전학회지
• /
• 제27권5호
• /
• pp.691-699
• /
• 2021

지난 한 세기 동안, 지구 표면 온도는 급격히 상승했다. 급격한 기온 상승은 심각한 지구 기후 변화를 초래한다. 2014년 IPCC 5차 평가보고서에 따르면 현재 추세대로 기온이 계속 상승하면 해수면 상승 현상처럼 자연 및 인간 체계에 위험이 가해지는 것으로 조사되었다. 해안 침식의 위험이 있는 모든 해안 지역들 중에서 기니만에 위치한 베냉은 매우 높은 취약 지역으로 나타났다. 이 보고서에서는 선행 연구들을 참고하여 코토누의 해안선 변화의 진행과정에 초점을 맞추어 이와 같은 변화의 영향을 조사하고, 연안 침식 방지 조치들의 적용 결과를 요약하였다. 베냉의 코토누에 있는 해안 침식의 징후는 1963년에 나타나기 시작했다. 코토누 동쪽의 해안선은 39년간 약 885 m 후퇴했고, 토지 손실과 함께 800여 채의 가옥이 없어졌다. 이 문제를 해결하기 위해 베냉 당국은 2013년에 7개의 돌제를 건설했고, 이후 추가 설치를 진행하였다. 설치 지역의 해안선은 해변 보호가 되고 있었다. 반면 돌제가 설치되지 않은 돌제 동쪽 지역은 연간 49 m의 집중 침식을 겪고 있다. 따라서 다음 단계로 돌제의 효과는 국지적 관점뿐만 아니라 더 넓은 관점에서 연구되어야 한다.