• Title/Summary/Keyword: Sea Field

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The Response of Temperature and Velocity Fields to $M_2$ Tide in Deukryang Bay in the Southern Sea of Korea (득량만에서의 $M_2$조에 대한 수온장 및 유속장의 응답)

  • HONG Chul-hoon;CHOI Yong-Kyu
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.4
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    • pp.667-678
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    • 1997
  • A primitive equation numerical model driven only by $M_2$ tide is used to examine role of tide in the temperature and velocity fields of Deukryang Bay. The numerical model reproduces several features of the observational temperature fields such that the isotherms tend to be parallel to the coast in the bay, and the colder water exists at the right hand side in the bay. The horizontal temperature and velocity fields in the model are dominantly influenced by bottom topography. The model also shows that the surface colder water in the bay is accompanied by strong-alongshore current during the flood tide. An investigation for baroclinicity in the bay by additional numerical experiment indicates that the baroclinirity in velocity field is very weak. The model, however, did not reproduce a stratification in the observation, implying that the model needs to add other semi-diurnal components such as $S_2,\;O_2\;or\;K_2$ tides to $M_2$ tide.

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Comparative Study of Ice Breaking Performance according to Scale of Sea Ice on Ice Field (실해역 해빙 크기에 따른 Araon호의 쇄빙성능 비교연구)

  • Lee, Chun-Ju;Kim, Hyun Soo;Choi, Kyungsik
    • Journal of Ocean Engineering and Technology
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    • v.28 no.1
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    • pp.28-33
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    • 2014
  • The Korean icebreaking research vessel "Araon" performed four sea trials in the Arctic and Antarctic Seas. The ice properties, such as the ice thickness, floe size, ice strength, and power of the vessel were quite different in these trials. To compare the speeds of ship with the same ice strength and power, the AARC (Arker Arctic Research Center) method is used with a vessel power of 10 MW and an ice strength of 630 Pa in this paper. Based on the analysis results, the speed of the ship was 1.62 knots (0.83 m/s) with a 1.02-m ice thickness and 2.5-km floe size, 5.3 knots (2.73 m/s) with a 1.2-m ice thickness and 1.0-km floe size, and 13.8 knots (7.10 m/s) with a 1.1-m ice thickness and 200-m floe size. The analysis results showed that the ship speed and floe size have an inversely proportional relationship. Two reasonable reasons are given in this paper for the final result. One is an ice breaking phenomenon, and the other is the effect of the ice floe mass. For the breaking phenomenon, the ice breaking force is very small because the ice floe is not breaking but tearing when a ship is passing through a small ice floe. Regarding the effect of the ice floe mass, it is impossible for a ship to push and tear an ice floe if the mass of the ice floe is too large compared to the mass of the ship. The velocity of the ship decreases when the ice floe has a large mass and a large size because the ship has to break the ice floe to move forward.

Hydrogeochemical Evaluation of Crystalline bedrock Grondwater in a Coastal Area using Principal Component Analysis (주성분 분석을 이용한 해안지역 결정질 기반암 지하수의 수리지구화학적 평가)

  • Lee, Jeong-Hwan;Yoon, Jeong Hyoun;Cheong, Jae-Yeol;Jung, Haeryong;Kim, Soo-Gin
    • Journal of Soil and Groundwater Environment
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    • v.22 no.3
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    • pp.10-17
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    • 2017
  • In this study, the evolution and origin of major dissolved constituents of crystalline bedrock groundwater in a coastal area were evaluated using multivariate statistical and groundwater quality analyses. The groundwater types mostly belonged to the $Na(Ca)-HCO_3$ and $Ca-HCO_3$ types, indicating the effect of cation exchange. Stable isotopes of water showed two areas divided by first and secondary evaporative effects, indicating a pattern of rapid hydrological cycling. Saturation indices of minerals showed undersaturation states. Thus, the degree of evolution of groundwater is suggested as in the low to intermediate stage, based on field and laboratory analytical conditions. According to the principal component analysis (PCA) results, the chemical components of EC, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $HCO_3{^-}$, $SO{_4}^{2-}$ (PCA 1), $F^-$ (PCA 3), $SiO_2$ (PCA 4), and $Fe^{2+}$ (PCA 5) are derived from various water-rock interactions. However, $NO_3{^-}$, $Na^+$, and $Cl^-$ (PCA 2) represented the chemical characteristics of both anthropogenic sources and natural sea spray.

Analysis of Wave Energy Density for Korean Coastal Sea Area Based on Long-Term Simulated Wave Data (장기 수치모사 파랑자료를 바탕으로 한 한국해역의 파랑에너지밀도 분석)

  • Song Museok;Kim Doyoung;Kim Min;Hong Keyyong;Jun Kichun
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.7 no.3
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    • pp.152-157
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    • 2004
  • Wave energy distribution along the Korean coastal sea area was analysed based on the calculated wave data at KORDI. The wave data for the analysis is for the last 24 years (1979∼2002) and the model is HYPA and WAM using known wind field. The wave energy or wave power was evaluated based on the linear wave theory with a simple wave period assumption. The results shed some idea on the amount of usable wave energy and the sites of higher efficiency. It is fair to say that 3kw/m wave energy is easily observable and 10kw/m is frequently available depending on the season and location. The south west region of Jeju island is believed to have the highest overall wave energy density.

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Evaluation of the CALPUFF Model Using Improved Meteorological Fields in Complex Terrain of East Sea Coast (동해안의 복잡지형에서 기상장 개선에 따른 CALPUFF 모델의 평가)

  • Lee, Chong-Bum;Kim, Jea-Chul
    • Journal of Korean Society for Atmospheric Environment
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    • v.25 no.1
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    • pp.15-25
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    • 2009
  • Donghae city is one of the most representative cement industrial city in Korea. The area is faced with the East Sea to the East and with high montane region of Tae-Back mountain range to the West. Many pollutant sources of air pollution are located near the coast, but the largest point sources of the region are located at the bottom of the mountain area in Donghae city. The local wind is highly affected by local topography and plays an important role in transport and dispersion of contaminants from the pollution sources. This study was designed to evaluate enhancement of MM5 predictions by using Four Dimensional Data Assimilation (FDDA), the SONDE data and the national meteorological station, data only. The alternative meteorological fields predicted with and without FDDA were used to simulate spatial and temporal variations of NOx in combined with Atmospheric Dispersion Models (CALPUFF). For the modeling domain, the alternative meteorological fields with 1.1 km spatial resolution were interpolated to the CALMET with 0.5 km resolution. The vertical layers set to have 35 and 12 layers for MM5 and CALPUFF, respectively. MM5 with the FDDA did not resulted in significant improvement of meteorological field prediction in Donghae region, which is primarily because of complex geography and wind scheme. The result of CALPUFF, however, showed reduction of uncertainty errors by using the interpolation scheme of the actual measurement data.

Generation of Tsunami Hazard Map (지진해일 재해정보도 제작)

  • Ahn, Seong-Ho;Ha, Tae-Min;Cho, Yong-Sik
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.4
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    • pp.127-133
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    • 2010
  • In the ocean area surrounding the Korean Peninsula, the undersea earthquakes have occurred frequently during last decades. The eastern coast of the Korean Peninsula is very vulnerable to tsunami attacks which occur along the Western Coast of Japan. In special, the middle areas of the eastern coast of Korean Peninsula have been damaged due to the Central East Sea Tsunami occurred in 1983. Thus, tsunami hazard mitigation becomes an important issue at eastern coastal communities. The countermeasures against unexpected tsunami attacks are not sufficient because the government policy generally focused on not preventing but recovering. In this paper, a hazard map based on the field survey and tsunami evacuation simulation is developed to mitigate tsunami damage at Imwon port, which was severely damaged during the 1983 Central East Sea Tsunami.

Benefit Analysis and Profit Business of Fishery Sector about Tidal Power Plant in Garolim Bay (가로림만 조력발전 사업관련 수산부문 수익사업 도출과 편익 분석)

  • Lee, Kwang-Nam;Jung, Jin-Ho
    • Journal of Fisheries and Marine Sciences Education
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    • v.27 no.1
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    • pp.218-229
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    • 2015
  • While promoting a variety of projects by using sea space, there has been a lot of social controversy among the stakeholders based on the results of the analysis. In particular, the benefits of fisheries sector were over-estimated and occurred a lot of opposition from fishermen and environment groups. In order to this solve, we have been studied focussed such as excavation of new projects, the method and result of the estimated benefits for fisheries sector. With regard to the tidal power plant of Garolim, we came up with five kinds of problems such as doing not reflect of the cost of the initial investment, over unit production, over unit price, excessive selection of breed, issues of cost of production in benefits study of fisheries sector derived previously. In order to these problems, we have derived new profitable projects based on the initial materials such as improvement of raising breed, discharge project of fingerlings and a small sea ranch project. As a result, previous study was analyzed in 30.2 billion won(1993), 54.8billion won(2009), but this study was estimated to 26.4 billion won and differences of benefits amount were occurred. In a previous study was calculated benefits by simple method, but this study came up with new projects for fisheries sector and because we estimated benefits considering new project. The method for benefits calculations for fisheries sector was not attempted in previous studies and in this study, we approached for the first time Also, in this study suggested new method to increase incomes fishermen such as development of suitable ranch breeding for the marine environment, ranch license(limited license), development of fisheries resources and the operation of fisheries facility. In the future, we hope to be helpful for the same field of study.

Growth of Two Native Zoysiagrasses Collected from Sea Side and Mountain Area in Indonesia on Growing Media Composed of Sand and Clay

  • Rahayu, Rahayu;Dewantoro, Hery;Arianto, Dwi Priyo;Bae, Eun-Ji;Choi, Su-Min;Lee, Kwang-Soo;Yang, Geun-Mo;Choi, Joon-Soo
    • Weed & Turfgrass Science
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    • v.7 no.1
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    • pp.54-61
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    • 2018
  • Zoysiagrass (Zoysia spp.) exists spotly in Indonesia and it has potential to be used in parks, golf courses, and football fields. Many football fields and golf course fairways use sand as top soil over native soil. This study aims to analyze growth and quality of two native zoysiagrasses Zis and Zim. Zis is a native zoysiagrass collected in sea-side and Zim is a native zoysiagrass collected in mountain area. Both types of zoysiagrasses were planted at field with altitude of 300 m with various growing media mixes of sand and reservoir's sediment. Thickness of the growing medium was 10 cm over an alfisol clay soil. Experimental plots were constructed using factorial completely randomized design with two native zoysiagrasses and 5 types of growing media. Two ecotypes of native zoysiagrasses showed different in growth habits combined with mixtures of growth media. Zim showed higher growing speed including more vigor with uniformity and texture than Zis. There were not significanthly differences on leaf color and root length between two ecotypes of native zoysiagrasses collected in Indonesia.

Comparison and Analysis on the Geophysical data Using Bathymetric Surveying Product (해저지형 측량성과를 이용한 지구물리자료 비교분석)

  • Kim, Yong-Cheol;Choi, Yun-Soo;Park, Byung-Moon
    • Spatial Information Research
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    • v.17 no.1
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    • pp.89-102
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    • 2009
  • The information of ocean topology is the fundamental source which is necessary for understanding the ocean, producing nautical charts and delimiting maritime boundaries. An echo sounder is being used generally to collect undersea bathymetric data, but an indirect method such as geophysical data acquired by satellites is being used recently. In this study, the outputs of ocean surveying for the production of the Basic Maps of the Sea in 1996 and 1997 in the East Sea and the bathymetric data produced by geophysical data are compared and analyzed. The study areas are Ulleung Plateau, Ulleung Basin and the southern area of Ulleung Basin which have different geophysical characteristics. Through this study, we found that the bathymetric data acquired by an indirect method using satellite is similar to the field surveying results in general configuration of ocean floor and average depth. However, the minimum square error is about 100m in 1700m depth, and it has been observed a local error up to 1000m. In addition, it has been found that the detailed undulation of ocean topology is shown on the gravity data which is acquired by the research vessel.

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An Empirical Study on the Determinants and Effects of Korean FDI in Manufacturing Industries (한국기업(韓國企業)의 해외직접투자(海外直接投資) 결정요인형태(決定要因形態)에 관한 실증(實證) 연구(硏究))

  • Lee, Eung-Kweon
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.27
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    • pp.183-213
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    • 2005
  • This study is achieving overseas investment to be kept and manages important position in business scope because Korean Company achieves business in major market in world and goes forward. under proposition that development(foreign direct investment) previous engagement can not but differ with advanced nation enterprise's model in over sea direct investment achievement. Grasp ramification(pattern change substance) of overseas direct investment since the 1990 to korean manufacture Firm(enterprise). Seek political consultation by analyzing change of factor and investment decision factor by year in dimension by industry investment winter season by year affecting in oversea direct investment and was attained in purpose to verify existent theory's explanation power connected with investment previous engagement. This is that can develop and procure competitive advantage of enterprise peculiarity by making overseas direct investment adversely with existent theory that can make foreign country direct investment though there is high position of enterprise characteristic's competitive advantage and move of knowledge and information is important in korean firm's overseas direct investment in globalization roadbed in at least own field through change and renovation establish experiment model under proposition that should grope more active previous engagement than advanced nation enterprise and arranged subject of study if it is korean's firm that wish to become universal guidance enterprise. and examine trend of direct investment and actual conditions invested first in the foreign countries as examples by investment department, by investment industry inside of investment scale etc..., establish korean firm's invest area selection and decision and investment very important person and effect analysis Circumstance-model that is based in strategic adaptedness by year. Circumstance-variable have influenced how in overseas direct investment and decision and what variable will be considered first in over sea direct investment did Empirical analysis in here after

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