• Title/Summary/Keyword: continental shelf

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Increasing demand formaritime security measures to streamline the maritime security (해양경비수요 증대에 따른 해양경비 효율화 방안)

  • Seo, Jin-Seok
    • Convergence Security Journal
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    • v.14 no.3_2
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    • pp.13-21
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    • 2014
  • Three sides by the waters of the country in which the topography of the peninsula is a treasure trove of natural resources in the country to recognize the importance of the sea and maritime territorial and maritime policy for the protection of rights, such as to promote the country striving to strengthen haeyangryeok. However, marine activities is 200 sea miles exclusive economic zone of the stage (EEZ) and the continental shelf extends as the, EEZ waters of the overlapping jurisdiction, Books sovereignty, marine scientific research and development, including the continental shelf surrounding the deepening relationship between the neighboring countries and complex understanding including international cooperation and coexistence between countries to be competitive. This time the Coast Guard 's maritime sovereignty existing patron driven from the accident prevention safety management system, from our sea, has been kept firmly. However, due to the new issue of disaster lies in the fate of marine police became dismantled. This real time so that you can be reborn as a marine police force structure. Structure to change the way the rescue operation. Expenses, Shore, you will need to increase the professionalism of pollution.

The Distribution and Feeding Characteristics of Some Dominant Polychaetes in the Continental Shelf of the East Sea, Korea (동해 대륙붕에 분포하는 주요 다모류의 서식지 환경)

  • Choi, J.W.;Koh, C.H.
    • 한국해양학회지
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    • v.21 no.4
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    • pp.236-244
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    • 1986
  • This study was carried out for appreciable information on the proper habitats and feeding modes of some dominant polychaetes in the continental shelf of the East Sea during April, 1985. Among 95 polychaete species, we select ed 9 dominant species in terms of their occurring frequency, abundance and population density. These are Terebellides stroemi, Chaetozone setosa, Magelona japonica, Ampharete arctica, Aglaophamus sinensis, Nothria holobranchiata, Lumbrineris japonica, Myriochele gracilis, Notoproctus pacificus. Major food item s of these species are centric diatoms and detritus. The feeding modes of the the m are mainly surtace or subsurface deposit feeding, though two specters, M.holobranchiata and L. japonica, could be assumed to be potential carnivores. To a certain degree, most deposit feeders in the coarse sediments showed selectivity in feeding and tube building. The feeding mode, gut content and the tube structure, and the distribution pattern of dominant polychaetes correspond well with the habitat tharacters, e.g.the bottom topography, the source of food and the sediment composition.

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Modeling of Tides in the Yellow Sea and the East China Sea using Dynamically Interfaced Nested Tidal Model (둥지형 동적결합 조석 모형을 이용한 황해 및 동중국해의 조석모형)

  • Choi, Byung-Ho;Hong, Sung-Jin
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.17 no.4
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    • pp.243-258
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    • 2005
  • A fully-nonlinear two-dimensional dynamically interfaced nested tidal model has been developed with improved efficiency, usability, relocatability and also adopting different time steps for economizing computational times, which is based on two-dimensional tidal model of Choi(1990) with resolution of $1/15^{\circ}$ inlatitude by $1/12^{\circ}$ in longitude covering the whole Yellow and East China Seas continental shelf. To illustrate the validity and applicability of the present model, numerical model experiment was carried out for tidal distribution in the Yellow Sea and the East China Sea emphasizing the Saemangeum area with enhanced grid system. The results from comparison with observed value showed that the present model gives reasonable agreement. The present modeling system is a relocatable tide forecasting system designed to predict tides at any location within the Yellow Sea and the East China Sea continental shelf sea.

Seasonal Cycle of Sea Surface Temperature in the East Sea and its Dependence on Wind and Sea Ice

  • Park, Kyung-Ae;Chung, Jong-Yul;Kim, Kuh
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.618-620
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    • 2003
  • Harmonics of sea surface temperature (SST) in the East Sea and their possible causes are examined by analyzing NOAA/AVHRR data, SSM/I wind speeds, NSCAT wind vectors, and NCEP heat flux data. Detailed spatial structures of amplitudes and phases of the seasonal cycles and their contributions to the total variance of SST have quantitatively. The Subpolar front serves as a boundary between regions of high annual amplitudes (${\geq}$10$^{\circ}$C) in the cold continental region and low amplitudes (${\leq}$10$^{\circ}$C) in the Tsushima Warm Current region. The low phase center of annual cycle is located over a seamount at 132.2$^{\circ}$E, 41.7$^{\circ}$N south of Vladivostok. Semi-annual amplitudes are significantly large leaching over 20% of the annual amplitudes in the Tatarskiy Strait and along the continental shelf off Russian coast in fall and spring, but its forcings are substantially annual. We have shown that fall cooling is attributed by direct and local wind forcing, while spring cooling is remotely forced by cold waters from sea ices in the Tatarskiy Strait.

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Distribution of Fish Larvae and Juveniles in the East China Sea and the Yellow Sea in Spring during 1994-1997 (1994-1997년 봄철 동중국해 및 황해 자치어 분포)

  • KIM Jin Koo;KANG Chung Bae;AHN Geon;OKI Daiju;KIM Yong Uk;TABETA Osame
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.38 no.1
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    • pp.29-38
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    • 2005
  • The distributions of fish larvae and juveniles from the East China Sea, Yellow Sea and near Tsushima Island were investigated in Spring using the Maruchi (1994-1995) and Unagi (1996-1997) nets. A total of 94 species of fish larvae and juveniles belonging to 49 families under 17 orders were identified, of which Engraulis japonicus was dominant in every year except 1995 where Trachurus japonicus was dominant. Cluster analysis based on abundance and species composition by sampling stations (St.) revealed that the similar stations formed an arcuate group from Tsushima Island to southern Jeju Island in 1994, and from the Yellow Sea to southern Jeju Island in 1996. We concluded that these patterns resulted from the influence of the Tsushima Current prevailing in the east, and the Chinese Continental Waters and/or Hwanghae Cold Waters prevailing in the west, with Jeju Island exerting an influence in the centre. The diversity and composition of St. 97-3 and St. 97-5, both located where the Tsushima Current splits from the Kuroshio Current, was greatly different despite their close proximity. However, the former is located on the continental shelf, with the latter on the continental slope. This suggested that both topography and the Kuroshio Current have the most influence on the distribution of fish larvae and juveniles in this region. Furthermore, the weak Hwanghae Cold Waters of 1997 may have also limited the mixing of fish larvae and juveniles between the two stations.

Organic Chemical Characteristics and Its Paleoceanographic Implications of the Holocene Sediments on the Continental Shelves Off the Southern Coast of Korea (남해 대륙붕 홀로세 퇴적물의 유기지화학적 특성과 고해양학적 의미)

  • Kong, Gee-Soo;Han, Hyun-Chul;Kim, Seong-Pil;Kim, Ji-Hun;Stott, Lowell
    • Economic and Environmental Geology
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    • v.42 no.2
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    • pp.107-120
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    • 2009
  • Spacial variation in organic components and temporal variation in the origin was examined through the organic geochemical (TC, TN, TS, $CaCO_3$, TOC, C/N, and $\delta^{13}C$) and pyrolysis analysis (HI, OI, and Tmax) in the core sediments which were acquired in the continental shelf of the South Sea close to Seomjin River. Levels of TC, TN, and TS show relatively low and constant in the core SJ03 located close to the Seomjin River mouth, while those are increased a little with being varied with low amplitude in the core SJ02 and SJ04 acquired at the middle of inner shelf area. They fluctuated with high amplitude in the core SJ01 and SJ05 near to the outer boundary of inner shelf. The vertical characteristics of organic components in the core SJ01 acquired at the outer boundary show that the area has undergone distinctly the environmental change at 9.0 kyr B.P. After 9.0 kyr B.P., Levels of TC, TOC, TN, $CaCO_3$, $\delta^{13}C$, HI, and Tmax are rapidly increased, while C/N and or are significantly decreased. Even though the contents of organic components are not high, such a changes reflect that the terrigenous organic matters were predominant before 9.0 kyr B.P due to the influence of Seomjin River, but after then, the marine organic matters have dominated due to the inflow of the Tshusima current.

Late Quaternary Seismic Stratigraphy and Sedimentation of the Southeastern Continental Shelf, Korea Strait (한국 남동해역(대한해협) 대륙붕지역의 후 제4기 탄성파 층서 및 퇴적작용)

  • Yoo Dong-Geun;Lee Chi-Won;Min Gun-Hong;Lee Ho-Young;Choi Joung-Gyu;Park Soo-Chul
    • Geophysics and Geophysical Exploration
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    • v.8 no.3
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    • pp.201-206
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    • 2005
  • Interpretation of high-resolution seismic profiles from the southeastern continental shelf of Korea reveals that the sedimentary deposits consist of seven seismic units formed during the late Quaternary. These units comprise lowstand, transgressive, and highstand systems tracts. The lowstand systems tract consists of a lowstand prograding wedge (SU1) and a mass flow deposit (SU2) including slumps and slides. The transgressive systems tract contains four seismic units: an ancient beach/shoreface deposit (SU3), a channel-fill deposit (SU4), a transgressive sand layer (SU5), and a transgressive sand ridge (SU6). The highstand systems tract consists of an inner-shelf mud deposit (SU7) derived from the Nakdong and Seomjin rivers during the last 6 ka when sea level was close to the present level.

Estimation of $^{210}Pb$-derived Sedimentation Rates in the Southwestern East Sea (동해 남서부 해역에서 $^{210}Pb$를 이용한 퇴적속도 추정)

  • Han, Jeong-Hee;Choi, Man-Sik
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.12 no.4
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    • pp.273-279
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    • 2007
  • In order to estimate the sedimentation rates of continental shelf and slope of Ulleung Basin in the Southwestern East Sea, $^{210}Pb,\;^{226}Ra\;and\;^{137}Cs$ were simultaneously measured by a well-type high purity germanium(HPGe) gamma detector. $^{137}Cs$ was used to determine whether the sediment were affected by bioturbation or not, and to judge the accuracy of estimated sedimentation rates. The estimated sedimentation rates decreased exponentially from slope to basin - 0.6 cm/yr in the continental shelf, $0.3{\sim}0.4$ cm/yr in the slope, and below 0.2 cm/yr in the margin of Ulleung basin. From our and other research results, we suggest followings about sediment transport of the study area. The sediment particles were transported by coastal current from south to north through the Korea Straight. And much of them were accumulated in the shelf area. And then, the rest of sediment particles were deposited in the lower slope and the southwest margin of the basin. Also the excess $^{210}Pb$ profiles indicate that the depositional processes in the study area may have been very complicate.

Organic Carbon, Calcium Carbonate, and Clay Mineral Distributions in the Korea Strait Region, the Southern Part of the East Sea

  • Khim, Boo-Keun;Shin, Dong-Hyeok;Han, Sang-Joon
    • Journal of the korean society of oceanography
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    • v.32 no.3
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    • pp.128-137
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    • 1997
  • This study presents results from a detailed sedimentological investigation of surface sediments obtained from the Korea Strait region, the southern part of the East Sea (Sea of Japan). The distribution of different types of bottom sediments is controlled by the recent fine-grained sediment transport and deposition combined with the lowerings of sea level during the last glacial period, forming a diverse mixture of organic-rich fine-grained and shelly coarse-grained sediments. In comparison to high organic concentration of fine-grained sediments in the inner continental shelf and slope areas, the shell-rich coarse-grained sediments on the outer shelf are discernible being further modified. These coarse-grained sediments are confirmed as relict resulting from the sediment dynamics during the lower sea levels of the last glacial period. Clay mineral distribution of the fine-grained sediments gives information about the transport mechanism. Presence of present-day current system (the Tsushima Warm Current) is most probable source for the fine-grained particles into the open East Sea from the East China Sea, indicating that Holocene sediment dynamics may be used to explain the observed distribution of surface coarse-grained shell-rich sediments.

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Evaluation and interpretation of the effects of heterogeneous layers in an OBS/air-gun crustal structure study (OBS/에어건을 이용한 지각구조 연구에서 불균질층의 영향에 대한 평가와 해석)

  • Tsuruga, Kayoko;Kasahara, Junzo;Kubota, Ryuji;Nishiyama, Eiichiro;Kamimura, Aya;Naito, Yoshihiro;Honda, Fuminori;Oikawa, Nobutaka;Tamura, Yasuo;Nishizawa, Azusa;Kaneda, Kentaro
    • Geophysics and Geophysical Exploration
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    • v.11 no.1
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    • pp.1-14
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    • 2008
  • We present a method for interpreting seismic records with arrivals and waveforms having characteristics which could be generated by extremely inhomogeneous velocity structures, such as non-typical oceanic crust, decollement at subduction zones, and seamounts in oceanic regions, by comparing them with synthetic waveforms. Recent extensive refraction and wide-angle reflection surveys in oceanic regions have provided us with a huge number of high-resolution and high-quality seismic records containing characteristic arrivals and waveforms, besides first arrivals and major reflected phases such as PmP. Some characteristic waveforms, with significant later reflected phases or anomalous amplitude decay with offset distance, are difficult to interpret using only a conventional interpretation method such as the traveltime tomographic inversion method. We find the best process for investigating such characteristic phases is to use an interactive interpretation method to compare observed data with synthetic waveforms, and calculate raypaths and traveltimes. This approach enables us to construct a reasonable structural model that includes all of the major characteristics of the observed waveforms. We present results here with some actual observed examples that might be of great help in the interpretation of such problematic phases. Our approach to the analysis of waveform characteristics is endorsed as an innovative method for constructing high-resolution and high-quality crustal structure models, not only in oceanic regions, but also in the continental regions.