• Title/Summary/Keyword: Coastal Areas

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Estimation of Atmospheric Dispersion Coefficients in A Coastal Area with Complex Topography (복잡한 지형의 임해지역에서 대기 분산계수의 평가)

  • 박옥현;천성남
    • Journal of Korean Society for Atmospheric Environment
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    • v.14 no.5
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    • pp.411-420
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    • 1998
  • To estimate the dispersion coefficients in a coastal area with complex topography, several schemes using empirical equations expressed with and in lateral and vertical directions, respectively have been examined. Estimation results using these equations and meteorological data obtained from SODAR system were compared' with previously measured dispersion coefficients in other coastal areas. Validations of estimation results have been performed by comparing the measured concentrations with predicted ones empolying in Boryung coastal area. Important conclusions were drawn as follows; (1) Variations of lateral and vertical wind direction revealed different height dependency in upper and lower mixed boundary layer. (2) Because of turbulent constraint effect by large water body in a coastal region, the lateral and the vertical dispersion coefficients were smaller than those of P-G system. (3) As a result of examining the performance measure of these schemes through checking of coincidence between measured and predicted concentrations, vertical dispersion coefficients were smaller than those of P-G system, and the Cramer scheme was found to be more appropriate rather than others in the coastal area surrounding Boryung power plant.

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The Restoration Effect of Deltacon Method in Coastal Erosion (Deltacon공법을 통한 해안 침식지의 복구 효과 연구)

  • Han, Bong-Ho;Park, Seok-Cheol;Lee, Poong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.20 no.6
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    • pp.35-50
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    • 2017
  • This study is to see the recovery effect of the Deltacon method by investigating the amount of sand deposition, the topographical cross section and the vegetation structure; and to derive the effective recovery method of coastal erosion area. The target areas of this study include Jinri coastal dune, Bajireum coastal dune and Seopori coastal dune in Deokjeok-do Island, Ongjin-gun, Incheon. In order to assess the current status of the coastal erosion area recovery, the soil profile structure map was prepared on the site and then the amount of sand deposition within 1m was calculated indoors. The vegetation recovery status of the costal erosion area was assessed via the analyses of the topographical profile structure and the plant community structure, and we aim to derive the effective recovery plan of the Deltacon method with the results. With the Deltacon method, structures with ductile material, special non-woven fabric bags filled with soil and vegetation can be performed therefore the structuralstability and prevention of sand erosion can be achieved. The amounts of sand deposition of Bajireum coastal dune, Seopori costal dune and Jinri costal dune were calculated $0.98{\sim}2.54m^3$, $1.02{\sim}2.96m^3$, and $0.27{\sim}0.75m^3$, respectively, and it is considered that the costal erosion recovery is actively performed for Bajireum costal dune and Seopori costal dune. The analysis results of vegetation structures by topography show that the installation of the send collecting net in steep areas has been highly effective and the Deltacon-constructed target areas have been restored to vegetation and the costal dune, which is similar to the natural dune. The investigation of the plant community structure in Deokjeok-do Island costal dune, Incheon displayed similar research results of the existing costal dune flora and confirmed the emergence of Lathyrus japonicus, Carex kobomugi, Elymus mollis, Vitex rotundifolia, and Calystegia soldanella and others. In order to carry out further effective recovery with the Deltacon method, improvements to rootage of herbaceous vegetation are needed in areas without foredune herbaceous vegetation, and continuos maintenance & management monitoring of connected windbreak forest to costal dunes are also necessary.

Identification of Visitation Density and Critical Management Area Regarding Marine Spatial Planning: Applying Social Big Data (해양공간계획 수립을 위한 방문밀집도 및 중점관리지역 규명: 소셜 빅데이터를 활용하여)

  • Kim, Yoonjung;Kim, Choongki;Kim, Gangsun
    • Journal of Environmental Impact Assessment
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    • v.29 no.2
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    • pp.122-131
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    • 2020
  • Marine Spatial Planning is an emerging strategy that promoting sustainable development at coastal and marine areas based on the concept of ecosystem services. Regarding its methodology, usage rate of resources and its impact should be considered in the process of spatial planning. Particularly, considering the rapid increase of coastal tourism, visitation pattern is required to be identified across coastal areas. However, actions to quantify visitation pattern have been limited due to its required high cost and labor for conducting extensive field-study. In this regard, this study aimed to pose the usage of social big data in Marine Spatial Planning to identify spatial visitation density and critical management zone throughout coastal areas. We suggested the usage of GPS information from Flickr and Twitter, and evaluated the critical management zone by applying spatial statistics and density analysis. This study's results clearly showed the coastal areas having relatively high visitors in the southern sea of South Korea. Applied Flickr and Twitter information showed high correlation with field data, when proxy excluding over-estimation was applied and appropriate grid-scale was identified in assessment approach. Overall, this study offers insights to use social big data in Marine Spatial Planning for reflecting size and usage rate of coastal tourism, which can be used to designate conservation area and critical zones forintensive management to promote constant supply of cultural services.

Environmental Factors and the Distribution of Eggs and Larvae of the Anchovy (Engraulis japonica) in the Coastal Waters of Jeju Island (제주도 주변해역의 해양환경요인과 멸치 난자치어 분포)

  • Ko, Joon-Chul;Yoo, Joon-Taek;Rho, Hong-Kil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.40 no.6
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    • pp.394-410
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    • 2007
  • Anchovy spawn from the end of May to mid-October, when the water temperature is $14.8-27.2\;^{\circ}C$ and the salinity is 26.0-33.6 psu. The main spawning season is between July to August, when the water temperature is $21.7-27.2\;^{\circ}C$ and the salinity is between 26.0-32.2 psu. The main spawning grounds of anchovy are coastal areas shallower than 50 m around the islands located in the Jeju Strait. Anchovy larvae are distributed near the fronts between Chuja-do, Jangsu-do, Yeoseo-do, and the open sea rather than in the spawning grounds. Anchovy eggs and larvae density increased in accordance with the high level of $Chlorophyll-{\alpha}$ during the summer season (July-August). In terms of the suspended sediment (SS) levels along the northern coast of the Jeju Strait, high densities of anchovy eggs (12.0-18.0 mg/L) were observed, mainly in the area affected by the coastal waters of the southern sea with high SS levels, while larvae (10.0-19.0 mg/L) tended to be distributed over a wide area with high SS levels, including the open sea. In terms of the dissolved oxygen (DO) content, eggs (5.4-6.8 mg/L) were observed in coastal areas with a high DO content, while larvae (4.2-6.4 mg/L) were distributed widely in areas with a relatively low DO content, from the southern coast to the open sea.

Characteristics of Ground Water Capture Zone according to Pumping Rate (지하수 양수량에 따른 지하수유동 및 포획구간 특성 변화)

  • Ahn, Seung-Seop;Park, Dong-Il;Oh, Young-Hun
    • Journal of Environmental Science International
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    • v.22 no.7
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    • pp.895-903
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    • 2013
  • This study analyzed on characteristics of the ground-water capture zone in coastal areas and mid-mountainous area according to pumping rate. For this study, it targeted Jejudo island where is the volcanic island. To analyze, MODFLOW model and MODPATH model, which are the ground-water flow analysis models, were used. As a result of research, the following conclusions could be obtained. As a result of analyzing influence of a change in pumping time upon length of capture zone, the length of capture zone in coastal area was indicated to be greater in the changing ratio compared to the length of capture zone in mid-mountainous area. Next, in the coastal area, the pumping rate and the capture-zone length are changing similarly. However, in mid-mountainous area, the length of capture zone was indicated to grow when the pumping rate comes to exceed 1,500m3/day. As a result of analyzing influence of a change in pumping time upon capture area, the tendency of a change in the area was indicated similarly in coastal areas and mid-mountainous area. Especially, it could be known that the larger pumping rate leads to the more definite increase in tendency to a change in capture area. Based on this study, it was allowed to be possibly used in the suitable pumping rate in coastal areas and mid-mountainous area of the volcano island in the future. A follow-up research is judged to necessarily analyze the influence of tubular-well group upon capture zone by additionally analyzing a change in capture zone targeting the concentrated tubular well.

Spatio-temporal Variation and Evaluation of Benthic Healthiness of Macrobenthic Polychaetous Community on the Coast of Ulsan (울산 연안 해역 저서다모류 군집의 시·공간 변동 및 저서건강도 평가)

  • Jeong, Bong Geun;Shin, Hyun Chool
    • Ocean and Polar Research
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    • v.40 no.4
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    • pp.223-235
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    • 2018
  • This study was carried out to investigate benthic sedimentary environments and benthic polychaetous communities on the coast of Ulsan, located on the southern East Sea of Korea. This survey was conducted at 15 stations, four times seasonally in January, April, July and October 2016. From the coast to the outer sea, surface sediments turned into fine grained sediments. There were complex coarse-grained sedimentary facies in various forms in the coastal zones while those with mud facies were found in the offshore zone. Organic matter content (LOI) and sulfide amount (AVS) recorded extremely high values, and increased from the coast to the outer sea, showing a similar trend to mud content with depth. The benthic polychaetous community revealed a mean density of $525ind./m^2$, and the total species number of species was 84. The major dominant polychaetous species were Magelona japonica, Lumbrineris longifolia and Heteromastus filiformis throughout the four seasons. Magelona japonica was concentrated predominantly in shallow coastal areas, but was present in all the regions of the survey area. Lumbrineris longifolia showed higher density in offshore regions more than 30 m deep, whereas H. filiformis showed higher density in coastal areas less than 30 m in depth. As a result of cluster analysis, the study area was divided into three ecological areas according to species composition, such as the northern coastal area between Ulsan PortOnsan Port, the southern area around Hoeya River and the outer sea area. Benthic environments in the study area, as determined by AMBI and BPI index, maintained a healthy condition in all four seasons with the AMBI at a level above GOOD and BPI at a level above FAIR. As organic matter accumulation continues to take place in the Ulsan coastal area, it is essential that detailed research activities continue to be carried out and ongoing monitoring be maintained.

Reproduction of Flood Inundation in Marine City, Busan During the Typhoon Chaba Invasion Using ADCSWAN and FLOW-3D Models (ADCSWAN과 FLOW-3D 모델을 이용한 태풍 차바 내습 시 부산 마린시티의 침수범람 재현)

  • Choi, Heung-Bae;Um, Ho-Sik;Park, Jong-Jib;Kang, Taeuk
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.26 no.7
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    • pp.881-891
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    • 2020
  • In recent years, large-scale development of coastal areas has caused the loss of many lives and extensive property damage in coastal areas, due to wave overtopping caused by high-wave invasion and strong typhoons. However, coastal inundation studies considering the characteristics of domestic coastal areas are insufficient. This study is a methodology study that aimed to reproduce inundation of surge and wave complex elements by applying the ADCSWAN (ADCIRC+SWAN) and FLOW-3D models. In this study, the boundary data (sea level, wave) of the FLOW-3D model was extracted using the ADCSWAN (ADCIRC+SWAN) model and applied as the input value of the FLOW-3D model and a reproduction was created of the Flooding due to surge and overtopping in Busan Marine City when the typhoon Chaba passed. In addition, the existing overtopping empirical equation and the overtopping calculated by the FLOW-3D model were compared, and for coastal inundation, a qualitative verification was performed using the Inundation Trace Map of Land and Geospatial Informatrix Corporation, and the effectiveness of this study was reviewed.

The influence of sea surface temperature for vertical extreme wind shear change and its relation to the atmospheric stability at coastal area

  • Geonhwa Ryu;Young-Gon Kim;Dongjin Kim;Sang-Man Kim;Min Je Kim;Wonbae Jeon;Chae-Joo Moon
    • Wind and Structures
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    • v.36 no.3
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    • pp.201-213
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    • 2023
  • In this study, the effect of sea surface temperature (SST) on the distribution of vertical wind speed in the atmospheric boundary layer of coastal areas was analyzed. In general, coastal areas are known to be more susceptible to various meteorological factors than inland areas due to interannual changes in sea surface temperature. Therefore, the purpose of this study is to analyze the relationship between sea surface temperature (ERA5) and wind resource data based on the meteorological mast of Høvsøre, the test bed area of the onshore wind farm in the coastal area of Denmark. In addition, the possibility of coastal disasters caused by abnormal vertical wind shear due to changes in sea surface temperature was also analyzed. According to the analysis of the correlation between the wind resource data at met mast and the sea surface temperature by ERA5, the wind speed from the sea and the vertical wind shear are stronger than from the inland, and are vulnerable to seasonal sea surface temperature fluctuations. In particular, the abnormal vertical wind shear, in which only the lower wind speed was strengthened and appeared in the form of a nose, mainly appeared in winter when the atmosphere was near-neutral or stable, and all occurred when the wind blows from the sea. This phenomenon usually occurred when there was a sudden change in sea surface temperature within a short period of time.

The Analysis of Coastal Landscape according to Development of Woljeong-ri Village in Jeju (제주 월정리 해안변 개발에 따른 해안경관 실태 분석 연구)

  • Seong, Da-Jeong;Park, Chung-Keun
    • Journal of the Regional Association of Architectural Institute of Korea
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    • v.20 no.6
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    • pp.33-40
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    • 2018
  • The coastal village in Woljeong-ri, Jeju is highly preferred by tourists because of its unique natural landscape different from inland areas. Especially, the number of buildings in the coastal area of the village is increasing due to escalating commercial value. Buildings are densely developed, along the seaside, resulting in privatization of coastal landscape. This results in blocking of landscape and psychological exchanges between the coastal village and coast. This study analyzed the actual conditions of coastal landscape before and after 2010, when the number of tourists and demand for development were increased in the coastal area of the coastal village in Woljeong-ri, Jeju. In this study, open index, visible horizontal index, elevation angle, elevation blockage and visible facade index were used to compute objective indicators of coastal landscape status. The analysis reveals visible facade index, a complex landscape assessment indicator, was increased by 7 times after 2010 as compared with before 2010. As such, there are many coastal villages in Jeju similar to Woljeong-ri that have a high landscape value and are in need of management. A comprehensive measure including a system for management of coastal landscape is urgently required to create narrative landscape in Jeju.

A Study on the Introduction of Impact Assessment System for Coastal Erosion (연안침식영향평가 제도 도입방안 연구)

  • Bum Shik Shin;Hyun Hwa Shin
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.36 no.2
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    • pp.87-93
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    • 2024
  • Recently, the impact of climate change with sea levels rise, abnormal high waves, and continuous construction of artificial structures such as ports and harbors, has led to an increasing trend in coastal erosion. In this study, the scope and method of Environmental Impact Assessment, Utilization of Sea Areas, Disaster Impact Assessment, and Risk Assessment of Coastal Disasters System, which are carried out during development projects and erosion reduction projects carried out on the coast, are analyzed to identify each problem. , we proposed a plan to introduce the Impact Assessment System for Coastal Erosion, which can minimize the impact of coastal erosion by deriving improvement measures.