• Title/Summary/Keyword: 서해

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GPS와 VLBI 관측소의 해수하중에 의한 수직방향 지각변위 평가를 위한 기초 연구

  • 박관동
    • Bulletin of the Korean Space Science Society
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    • 2003.10a
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    • pp.30-30
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    • 2003
  • GPS와 VLBI와 같은 우주측지 기술을 이용한 정밀 측위는 수 mn 정밀도의 관측소 좌표결정과 1 mm/year 정도의 고정밀 속도결정에 이용된다. 이를 위해서는 여러 가지 오차 요인들과 다양한 물리적 현상에 대한 모델링이 이루어져야 한다. 그 중의 하나가 해수 하중(ocean loading)에 의한 수직방향의 지각변위이다. 특히 한반도의 서해안은 복잡한 리아스식 해안으로 이루어져 있고, 조수간만의 차이가 크기 때문에 현존하는 모델의 정확도가 떨어진다. KVN(Korean VLBI Network)사업에서 추진하는 3기의 VLBI 중 2기가 서울과 제주도에 설치될 계획이므로, 해수하중에 의한 지각변위에 관한 연구가 선행되어야 한다. 또한 국내 GPS상시관측소의 많은 수가 서해안 지역에 설치되어 있다. 본 연구에서는 서해안 지역의 해수하중에 의한 수직방향의 지각변위를 GPS로 관측하고 이를 서해안 해수조류 모델의 정밀도를 향상시키는데 필요한 기초연구를 수행하였다. 서해안의 4개 GPS 관측소 위치에서의 해수하중에 의한 지각변위를 계산해본 결과 인천 지역에는 3 cm에 육박하는 지각변위가 수직으로 발생함을 알 수 있었다. 같은 크기와 위상의 지각변위 진폭을 GPS로 검출하기 위한 여러 가지 오차 보정과 GIPSY를 이용한 고정밀 키네마틱 GPS 자료처리에 대하여 상세히 소개한다.

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Analyzing the characteristic of coast environment in Seo-han bay, North Korea using satellite images and GIS (위성영상과 GIS를 이용한 북한 서한만의 연안환경 특성 분석)

  • 조명희;유홍룡;김형섭;김성재;허영진
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • 2004.03a
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    • pp.593-598
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    • 2004
  • 본 연구에서는 위성영상자료 Landsat TM(1999.8.16), ETM+(2002.9.17)을 활용하여 북한 서한만 지역의 NDVI, 토지피복, 지표온도 분포도를 작성하여 경년에 따른 환경변화를 탐지 및 분석하였으며 ISODATA Clustering 기법을 적용하여 북한 서한만 일대의 간석지 분포도를 작성하였다. 북한 서해안 간석지 면적변화 탐지를 위하여 고지형도 (1918)를 디지털 자료로 변환하여 북한 서해안 전역의 간석지 GIS DB를 구축하였으며 위성영상자료를 이용하여 작성된 간석지 공간 분포도와의 비교ㆍ분석을 통하여 북한 서한만 일대의 84년간의 간석지 면적변화를 탐지하였다. 이러한 연구 결과를 바탕으로 북한 서해안 지역의 간석지 퇴적 환경정보 및 다양한 연안 환경정보를 구축할 수 있었으며 북한 서해안 지역과 남한 서해안 지역의 간석지 연안환경 비교 분석 등을 위한 기초자료로 활용될 것으로 판단된다.

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Underwater acoustic communication system using diversity based on ray modeled underwater acoustic channel in Yellow Sea (다이버시티 기법을 이용한 서해에서의 음선 모델기반 수중음향통신 시스템)

  • Kang, Jiwoong;Kim, Hyeonsu;Ahn, Jongmin;Chung, Jaehak
    • The Journal of the Acoustical Society of Korea
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    • v.35 no.1
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    • pp.1-7
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    • 2016
  • This paper proposes an adequate UWA (Underwater Acoustic) communication system of underwater communication network in the Yellow Sea. UWA channel is obtained from Bellhop ray tracing method with Yellow Sea environments. Based on this channel, communication parameters for CDMA (Code Division Multiple Access) and SC-FDM (Single Carrier-Frequency Division Multiplexing) using diversity techniques are calculated. In order to prove the proposed methods, BER (Bit Error Rate) and data rate are obtained using computer simulations and the adequate communication system for long rms delay spread and low Eb/No environments is proposed from the simulation.

Maturation and Spawning of the Pacific Cod Gadus macrocephalus in the West Coast of Yellow Sea of Korea (한국 서해에 출현하는 대구(Gadus macrocephalus)의 성숙과 산란)

  • Choi, Dong Hyuk;Youn, Byoung Il;Kim, Maeng Jin;Lee, Seung Hwan;Lee, Seung Jong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.54 no.1
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    • pp.46-52
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    • 2021
  • The maturation and spawning of Pacific cod Gadus macrocephalus were inversigated using 2,415 samples collected monthly from January 2017 to December 2019, in the Yellow Sea of Korea. We analyzed monthly changes in gonadosomatic index (GSI), maturity stage, egg diameter (mm), the relations fecundity and total length (cm). The spawning period was February to March. Fecundity varied between 334,836 and 2,099,600 eggs. The relationship between the fecundity and TL of fish was expressed in F=186.86TL2.0954 (R2=0.7359). The percentage of sexually mature females estimated from a logistic function was over 50%, 75% and 97.5% for the size (TL) 39.3, 44.8 and 57.7 cm.

Feeding Habits of the Marbled Flounder Pseudopleuronectes yokohamae in the West Sea in Korea (한국 서해에 출현하는 문치가자미(Pseudopleuronectes yokohamae)의 식성)

  • Roh, Tae Hyoung;Choi, Dong Hyuk;Lee, Seung Hwan;Kwon, Dea Hyeon;Han, Kyeong Ho;Kim, Maeng Jin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.55 no.5
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    • pp.583-589
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    • 2022
  • The feeding habits of the marbled flounder Pseudopleuronectes yokohamae were studied using 384 specimens (10.7-52.3 cm in total length) collected from the West Sea, Korea between January and December 2021. P. yokohamae ate mainly polychaeta and gastropoda, incuding teleostei, caridea, euphausiacea, amphipoda and brachyura. The mean number of preys per stomach (mN/ST) showed a statistically significant difference, and the mean weight of prey per stomach (mW/ST) increased as the total length increased. P. yokohamae ate mainly teleostei in spring and winter. P. yokohamae ate mainly euphausiacea in summer and mainly polychaeta in autumn.

Maturity and Spawning of the Pointhead Flounder Cleisthenes pinetorum in the West Sea of Korea (한국 서해에 출현하는 용가자미, Cleisthenes pinetorum 암컷의 성숙과 산란)

  • Choi, Dong Hyuk;Youn, Byoung Il;Lee, Seung Hwan;Kwon, Dae Hyeon;Kim, Maeng Jin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.55 no.5
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    • pp.575-582
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    • 2022
  • This study revealed the reproductive biology of pointhead flounder Cleisthenes pinetorum, in the middle of the West Sea of Korea. We collected samples using gill net and drag net fisheries in coastal waters from January to December 2019. Mmonthly gonodosomatic index and maturity stage results showed that the spawning period was October to December, and the females grew faster than the males. The fecundity ranged from 16,728 to 1,039,616 number of eggs, and the relationship between TL and fecundity (F) was 0.0000003TL4.7434 (R2=0.4898). The size-frequency distribution of eggs suggested that C. pinetorum spawm once during a spawning period. The length at 50% maturity for females was estimated to be 18.9 cm.

Spatial Distribution and Time Variation of M2 Tide and M4 Tide in the Western Coast of Korea (서해 연안해역에서 M2 분조와 M4 분조의 분포 및 변화)

  • Jung, Tae Sung;Jeong, Jin Kwang
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.25 no.4
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    • pp.255-265
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    • 2013
  • In the coastal region of Korea, historical tide harmonic constants were collected. Long-term tides and short-term tides observed by the KHOA were analyzed by a tide harmonic analysis method. Based on the harmonic constants, tidal characteristics such as tide asymmetry in Korean coastal waters were investigated. The harmonic constants obtained from the long-term tide data in the western coast have been used to show the relation between tide variation and reclamation project. $M_2$ amplitudes in the western coast have been decreased and $M_2$ phases were faster. $M_4$ amplitudes also were reduced and $M_4$ phases were faster in overall. In Mokpo and Kunsan tidal nonlinearity is relatively conspicuous. Overall, non-linearity of tidal currents is higher in the tidal channels flowing fast. The tidal non-linearity has increased by the development projects including large reclamation. The flood dominant characteristic in the northern and central part of Korean western coastal waters and the ebb dominant characteristic in the southern part have been intensified. The construction of Saemangeum sea dike has significantly changed the tidal characteristic in Korean western coastal waters.

Snowfall and Ocean Conditions Characteristic in the West Sea of Korea in Winter (동계 서해의 해황과 적설 특성)

  • Go, Woo-Jin;Kim, Sang-Woo;Jang, Lee-Hyun;Choi, Yong-Kyu;Yang, Joon-Yong
    • Proceedings of KOSOMES biannual meeting
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    • 2008.05a
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    • pp.185-189
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    • 2008
  • This study was conducted to find out the effects of relationship between ocean conditions and snowfall when cold and dry continental air mass passes through the West Sea of Korea. Route of continental high atmospheric pressure can cause effect on snowfall at the west regions (Inchoen, Gunsan, Mokpo) of the Korean Peninsula. The continental high atmospheric pressure extend from the southern China to western coastal region of the Korean Peninsula during the December, and it extend from the north side of China through Bohai Sea and Yodong Peninsula to central area of the Korean Peninsula during the February. Therefore, more snowfall recorded in Incheon is higher during Feb. than Dec.. whereas Gunsan and Mokpo is the opposite. The heavy snowfall at the western coastal region of Korea was caused by loss of the heat from the ocean to air when it's higher than $100W/m^2$. the heavy snowfall was also observed when the arrangement of continental high atmospheric pressure and low pressure was high at the West and low at the East, which formed a front in West and when the wind blow from the North or North West at the speed of $4\sim8m/sec$. There were not much relation between salinity in the western sea and snowfall in the western coastal region of Korea.

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Changes of Serum Chemistry Values on Size and Cultured Method in Korean Rockfish, Sebastes schlegeli (사육방법 및 크기에 따른 조피볼락의 혈청 화학성분 변화)

  • Jung, Sung-Hee;Seo, Jung-Soo;Choi, Hye-Sung
    • Journal of Fisheries and Marine Sciences Education
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    • v.26 no.4
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    • pp.695-704
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    • 2014
  • The purpose of this study was to obtain reference values of serum chemistry in Korean rockfish (Sebastes schlegeli), 5 juvenile (n=25) and 3 broodstock (n=15) subpopulations which were differentiated by cultured method. Serum samples were analyzed for the following commercial clinical kits: total protein, albumin, glucose, AST (aspartate aminotransferase), ALT (alanine aminotransferase), total cholesterol, free cholesterol, LDH (lactate dehydrogenase) and ALP (alkaline phosphatase). Significant differences were observed in the values of total protein, albumin, total cholesterol, AST, ALT, LDH and ALP between juvenile and broodstock subpopulations. In the comparison of total protein, albumin, total cholesterol and ALP, broodstock subpopulations showed higher levels. On the other hand, increased AST, ALT and LDH were observed in juvenile subpopulations. These results indicate that cultured method are major contributors to health-related physiology of Korean rockfish, juveniles and broodstocks.

Occurrence Patterns of Zooplankton Present in Ports of Korea during Summer (한국 주요 항에 출현하는 하계 동물플랑크톤 군집 특성)

  • Seo, Min Ho;Shin, Kyeongsoon;Jang, Min-Chul;Soh, Ho Young
    • Korean Journal of Environmental Biology
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    • v.31 no.4
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    • pp.448-457
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    • 2013
  • Zooplankton community in the major ports of Korea, which were characterized by a specific marine environmental condition during summer, was studied. Water temperature in the ports of western areas was higher and while those in the East Sea was lower. Contradictorily, the salinity was lowest in the western areas, while being highest in the eastern area. The Chl-a concentration was highest in the southern areas and lowest in the eastern one. Zooplankton taxa were most diverse in the western areas and simplest in the eastern one. Copepods predominantly occurred in the western areas, but their abundance relatively decreased in the southern and eastern areas. Cluster analysis revealed that copepod communities were classified into 3 summit groups, the western, southern and eastern areas. The results indicate that zooplankton communities in Korean ports may be affected by biological factors like Chl-a concentration in addition to environmental factor such as temperature and salinity.