• 제목/요약/키워드: coastal current

검색결과 1,065건 처리시간 0.024초

Sea Prince호 유류유출 후의 남해안 소리도-금오도 주변 연성퇴적물 대형저서동물의 군집구조 (Community Structure of Soft-bottom Macrozoobenthic Communities near the Sori-Keumo Islands, Southern Coast of Korea after the Sea Prince Oil Spill)

  • 최진우;서진영;임현식;신현출
    • 한국수산과학회지
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    • 제39권spc1호
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    • pp.151-164
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    • 2006
  • We monitored the current macrozoobenthic community structure after the Sea Prince oil spill around Keumo-do and Sori-do, Korea. Macrobenthic animals were collected seasonally around Sori-Keumo do using a van Veen grab ($0.1m^2$) from October 1999 to April 2000. In total, 196 species were identified at 46 sites around Keumho-do. The mean density was 1,460 individuals/$m^2$, and polychaetes comprised 80% of the total density of the macrozoobenthic. Dominant species were the polychaete Tharyx sp. (51%), the echinoderm Amphioplus megapomus (5%) and the polychaete Lumbrineris longifolia (3%). We identified 176 macrobenthic species at 36 sites around Sori-do. The mean density was 1,068 individuals/$m^2$, and polychaetes was the most abundant faunal group, comprising 41%, followed by mollusks (24%) and echinoderms (20%). Dominant species in Sori-do were the mollusk Potamocorbula amurensis (23%), the chinoderm Amphioplus megapomus (14%), and the polychaete Tharyx sp. (10%). The overall community structures in the study area showed few seasonal changes, although there was a gradual change in the species composition within each benthic community. Tharyx sp. was the most abundant species in the study area. Because this species has not been found in the other coastal areas except during recent investigations, it is considered to have increased during the course of community succession after the oil spill. The macrozoobenthic around Keumo-do showed little change in species richness, whereas around Sori-do, it showed a few increases in species richness after the summer of 1998. The overall density showed the same trend as species richness. Based on improved community indices, we suggest that the macrozoobenthic communities around Sori-Keumo Islands are gradually recovering from the oil-spill damagecaused by the oil spill.

Wind-induced Spatial and Temporal Variations in the Thermohaline Front in the Jeju Strait, Korea

  • Han, In-Seong;Suh, Young-Sang;Seong, Ki-Tack
    • Fisheries and Aquatic Sciences
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    • 제16권2호
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    • pp.117-124
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    • 2013
  • We investigated the short-term and local changes in the thermohaline front in the Jeju Strait, Korea, which is usually formed during winter and spring. To do so, we compared Real-Time Observation System by Ferryboat (RTOSF) data with wind data and routinely collected oceanographic data. During February and April 2007, a thermohaline front formed in the Jeju Strait around the 13-$14^{\circ}C$ isotherms and 33.0-33.5 isohalines. The thermohaline was clearly weakened and began moving southward in mid-March. The variations in the surface temperature and salinity showed a continuous north-south oscillation of the thermohaline front with a period of 3-10 days. The speed of the short-term and local fluctuation of thermohaline front was about 5-30 cm/s. We confirmed these findings by examining the variation in the maximum temperature gradient and $14^{\circ}C$ isotherm during the study period. These short-term and local changes had not been previously detected using serial oceanographic and satellite data. Analysis of local wind data revealed a northerly wind fluctuation with a period of 3-10 days, which was clearly related to the short-term and local changes in the thermohaline front. The short-term and local changes of the thermohaline front in the Jeju Strait originated from local changes in the winter monsoon in this area.

화력발전소 회처리장 조성에 따른 환경영향 최소화를 위한 석탄회 재활용 확대방안에 관한 연구 (A Study on Expanding the Recycling of Coal Ash for Minimizing Environmental Impact Imposed by the Establishment of Thermal Power Plant Ash Ponds)

  • 서동환;맹준호
    • 환경영향평가
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    • 제24권5호
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    • pp.472-486
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    • 2015
  • 국내 석탄화력발전소에서는 매년 800만 톤 이상의 석탄회가 배출되고 있으며, 이에 대한 최종적인 처리는 현재 약 70% 수준의 재활용, 그리고 해안 회처리장을 통해 매립 처리하고 있다. 그러나 실질적으로 개별 발전시설의 회처리장마다 수년 내에 만지(포화) 시기의 도래가 예상되며, 석탄회처리장 건설로 인한 환경영향에 대한 우려로 신규 확보도 어려운 상황이다. 향후 "제7차 전력수급기본계획"을 반영하여 추가적으로 건설될 석탄화력 발전시설을 고려했을 때(2020년 기준 1,000만 톤 배출 예상), 회처리장의 신규조성이 불가피하다. 그러나 회처리장 조성으로 인해 기존의 양호한 자연해안지역이 훼손되는 문제가 우려될 수 있다. 따라서 본 연구에서는 석탄회로 인한 환경영향을 최소화하기 위해, 근본적으로 추가적인 석탄화력 발전시설과 회처리장의 건설을 줄여나가고 더불어 배출된 석탄회의 유효이용 및 재활용 활성화를 위한 정책적 방안을 제시하고자 하였다.

Eddy-Resolving Simulations for the Asian Marginal Seas and Kuroshio Using Nonlinear Terrain-Following Coordinate Model

  • Song, Y.-Tony;Tang, Tao
    • Journal of the korean society of oceanography
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    • 제37권3호
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    • pp.169-177
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    • 2002
  • An eddy-resolving free-surface primitive-equation model with nonlinear terrain-following coordinates is established to study the exchange of water masses among the Asian marginal seas and their adjacent waters. A curvilinear coordinate system is used to generate the horizontal grid with a variable resolution for the regional oceans from $5^{\circ}$S to $45^{\circ}$N and $100^{\circ}$E to $155^{\circ}$E. The higher resolution region has about a 10 km by 10 km grid covering the complex geometry of the coastal marginal seas, while the lower resolution region has about a 30 km by 30 km grid covering the eastern Pacific. The model is initialized by the Levitus annual climitology and forced by the monthly mean air-sea fluxes of momentum, heat, and freshwater derived from the Comprehensive Ocean-Atmosphere Data Set. High-resolution and low-viscosity are identified as the key factors for a better representation of the exchange of waters through narrow straits and passages between the marginal seas and their adjacent waters. The dynamics of the loop currents and eddies in the South China Sea and Celebes Sea are examined in detail. It has found that the anticyclonic loop and detached eddies from the Kuroshio through the Luzon Strait play an important role in transporting warm and salty water into the South China Sea, while the cyclonic circulation of the Mindanao Current in the Celebes Sea plays a role in contributing cold water to the Indonesian throughflow. The deep undercurrent of the western Pacific is shown to provide fresher water to the South China Sea and Celebes Sea. These modeling results suggest that the exchange processes via the narrow straits and passages are of fundamental importance to the maintenance of water masses for the marginal sea region.

여수연해 정치망어장의 해황과 어황에 관한 연구 (Oceanographic Condition and Fishing Condition of the Set Net Fishing Ground in Yeosu Bay)

  • 김동수;이조출;박용석
    • 수산해양기술연구
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    • 제24권4호
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    • pp.150-157
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    • 1988
  • 여수연해 정치망 어장의 6월, 7월, 8월의 해황변화에 따른 어황관계를 조사하고 분석한 결과는 다음과 같다. 1) 하천수의 유입이 많은 내해와 돌산연안의 정치망 어장에서는 고온.저염분수가 분포하고 외해에는 저온 고염분수가 분포한다. 2) 정치망 어장부근에는 6월의 와류형성과 8월의 수온약층 형성으로 어류가 군집을 하는데 영향을 미쳐 좋은 어획량을 보여 주고 있다. 3) 정치망 어장에서 어획수온범위는 11$^{\circ}C$~28$^{\circ}C$이며 좋은 어획량을 나타내는 범위는 21$^{\circ}C$~27$^{\circ}C$였다. 또한 염분의 범위는 31.60$\textperthousand$~34.80$\textperthousand$이고 어획이 가장 좋은 범위는 33.80$\textperthousand$~33.99$\textperthousand$였다. 4) 어획대상물의 어획순위는 삼치, 전갱이, 삼치, 정어리, 고등어, 갈치의 순으로 나타났다.

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강릉지역 2009~2018년 해풍 발생 특성 (Occurrence Characteristics of Sea Breeze in the Gangneung Region for 2009~2018)

  • 황혜원;은승희;김병곤;박상종;박균명
    • 대기
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    • 제30권3호
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    • pp.221-236
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    • 2020
  • The Gangneung region has the complicated geographical characteristics being adjacent to East Sea and Taeback mountains, and thus sea breeze could play an important role in local weather in various aspects. This study aims to understand overall characteristics of sea breeze largely based on long-term (2009~2018) ground-based observation data. We also propose a selection criteria of sea breeze occurrence day; 1) daily precipitation is less than 10 mm, 2) surface wind direction is 0~110° (northerly to easterly) for more than 3 hours during the daytime, 3) wind direction is 110~360° for more than 3 hours during the nighttime, and 4) land and sea temperature difference is positive during the daytime, 5) sea and land sea-level pressure difference is more than 0.5 hPa. As a result, a total of 595 days was selected for the past 10 years. The occurrence of sea breeze is the highest in late Spring to early Summer (May to June). The passage time of sea breeze at the inland station (1.6 km farther inland) is one hour later than the coastal station. On the typical sea breeze event of April 12, 2019, the passage speed and duration of sea breeze was 15 km hr-1 and about 9 hours, respectively, with its depth of about 500 m and its head swelling. The current results emphasize the critical role of sea breeze in forecasting surface temperature and wind, and contribute to relieve heat wave especially in summer in the Yeongdong region.

해적행위의 본질, 발생현황 및 조직.기술적 대응 방안에 관한 연구 (Piracy: Its Nature, Development and Countermeasures)

  • 최진태
    • 해양환경안전학회지
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    • 제4권2호
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    • pp.69-83
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    • 1998
  • Sea transportation has long been a vital component of the transport systems of the world. The great majority of imports and exports to and enlarge their national merchant marines. This effort is meant partly to arrest earlier trends of having their trade carried by ships from outside the region and partly to promote regional integration and improve the national balance of payments. However, sea transportation has been exposed to various types of threats on the high seas, in coastal waters and in port areas. Piracy is any robbery or other violent action, for private ends and without authorization by public authority, committed on the seas. Because piracy has been regarded as an offense against the law of nations, the public vessels of any state have been permitted to seize a pirate ship, to bring it into port, to try the crew(regardless of their nationality or domicile), and, if found guilty, to punish them and to confiscate the ship. Piracy has occurred in all stages of maritime history. The increased size of merchant vessels, the improved naval patrolling of most ocean highways, the regular administration of most islands and land areas of the world, and the general recognition by governments of piracy as an international offense resulted in a great decline in piracy in the 19th and 20th centuries. Piracy has, however, occurred in the 20th century, and the practice of hijacking ships has developed into a new form of piracy. The number of incidents of sea piracy against ships reported was 229 in 1997. Since 1991, 1,051 such acts have been reported. The purpose of this research is to examine the origin and development of the piracy to understand the current situation of such violence on the seas. In addition, what should be done by international community will be presented to prevent the piracy in the future.

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해상교통안전진단 사후관리제도의 도입 및 제도개선에 관한 고찰 (A Study on Adopting an Ex Post Facto Management System and Reforming the Maritime Traffic Safety Audit Scheme)

  • 김인철
    • 해양환경안전학회지
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    • 제22권7호
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    • pp.807-813
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    • 2016
  • 해상교통안전진단제도는 연안에서 선박의 항행에 영향을 미치는 각종 해상사업으로 인해 발생할 수 있는 위험요인을 전문적으로 조사 측정 평가하기 위해 2009년에 법제화된 이후에 제도 발전에 관한 여러 연구가 수행되어 왔다. 이러한 연구결과를 분석하여 현제도의 미비점을 색인한 결과, 안전진단 결과에 따라 해상사업이 수행되었는지 검증하기 위한 절차와 안전진단의 주요 과정 중 하나인 선박조종 시뮬레이션의 정확성을 검증하기 위한 사후관리 관련 규정이 미흡했다. 사후관리제도 도입 필요성이 드러남에 따라 법령화된 유사 제도인 환경영향평가제도와 도로교통안전진단제도의 법체계를 분석하였다. 그리고 해상교통분야의 미비점을 개선하기 위한 법령안을 구체적으로 제시하였다. 본 고의 법령안은 진단의 정확도를 검증하고 진단결과의 이행을 담보함으로써 해상사업과 관련된 잠재적 위험요인을 제거하고 해상교통안전에 기여할 것으로 기대된다.

Bayesian state-space 모델을 이용한 말쥐치 자원평가 및 관리효과 분석 (Assessing Stock Biomass and Analyzing Management Effects Regarding the Black Scraper (Thamnaconus modestus) Using Bayesian State-space Model)

  • 최민제;김도훈;이해원;서영일;이성일
    • Ocean and Polar Research
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    • 제42권1호
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    • pp.63-76
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    • 2020
  • This study sought to assess the stock status and analyze the management effects with regard to the Black scraper, which is one of the more commercially important species in Korea. The catch amounts of Black scraper have significantly decreased since 1991. In this analysis, a Bayesian state-space model was utilized to assess the biomass of the Black scraper given the limited data. Model results showed that MSY and BMSY of Black scraper were estimated to be 26,587 tons and 365,200 tons, respectively. In addition, the current biomass level of the Black scraper was assessed to be only 2.1% (7,549 tons) of BMSY. For this reason, the effects of a moratorium policy on the Black scraper were evaluated. The results showed that if such a moratorium policy was implemented, it would take at least 18-40 years to restore the biomass level of the Black scraper to BMSY depending upon its growth rates.

새만금간척전 .후 잔차류의 계절변화에 관한 연구 (A study of seasonal variation of the residual flow before and after Saemangeum reclamation)

  • 신문섭
    • 한국농공학회:학술대회논문집
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    • 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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    • pp.155-161
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    • 1999
  • The land reclamation area of Saemangeum(Kunsan) is located between 126$^{\circ}$10' E~126$^{\circ}$50' E and 35$^{\circ}$35' N~356$^{\circ}$05'N at the western coast of the Korean peninsula. The are many small islands including extensive areas of semi-diurnally flooded and dewatered tidal flats. The reclamation area of Saemangeum has a range of 5.6m spring tide and the maximum tidal current speed is about 1.41m s-1 in ordinary spring tide. Most of the sediments deposited on the tidal flats are transported from the Geum river, the Manjyung river and The Dongjin river. The soil in this area consists of silty sand with the depth of 10m to 30m . The wind in winter is strong from the direction of northwest. In the past twenty years, land reclamation projects for agricutural purpose or industrial cocmplex have been mostly implemented along the western coast of Korea. Saemangeum coastal area is being constructed the33km sea dike and 40, 100ha reclamation area. The purpose of this study is to find the residual circulations in four seasons after the dike construction by a robust diagnostic and prognostic numerical model. Heat flux at the sea surface in January ,May , August , October was asopted on the basis on the daily inflow of solar radiation at the earth surface, assuming an average atomospheric transmission and no clouds , as a function of latitude and time of year(George L.P.J.E William, 1990). The discharge from the Geum , the Mankyung and the Dongjin rivers was adopted on the basis of experience formula of river flow in January , May ,August, October (The M. of C.Korea, 1993) . Water temperature and salinity along the open boundaries are obtained from the results of field observation s.

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