• Title/Summary/Keyword: West sea

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Predicting Changes in Fishing Conditions for the Small Yellow Croaker Larimichthys polyactis based on Expansions of the Yellow Sea Bottom Cold Water (황해저층냉수에 따른 참조기(Larimichthys polyactis) 어황의 변화와 예측 가능성)

  • Lim, Yu Na;Kim, Heeyong;Kim, Dae Hyun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.47 no.4
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    • pp.419-423
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    • 2014
  • We consider changes in the fishing ground of the small yellow croaker Larimichthys polyactis and discuss their utility in predicting fishing conditions for this species. The fishing ground, which having been formed around Jeju Island since the 1970s, is dominated by the Yellow Sea Bottom Cold Water (YSBCW), and variation in its southward expansion from the Yellow Sea is the single most key environmental factor affecting the L. polyactis catch. When the YSBCW showed strong expansion and the fishing ground shifted to the west and southwest of Jeju Island, as occurred in the late 1980s, late 1990s, and early 2000s, the L. polyactis catch was low; conversely, when expansion was weak, as in the early 1990s and late 2000s, the L. polyactis catch was high. This relationship was statistically significant and should be useful in predicting fishing conditions for L. polyactis.

Conceptual Design of Deep-sea Multi-Point Mooring by using Two-Point Mooring (2점지지계류를 활용한 심해 부유체의 다점지지계류 개념설계)

  • Park, In-Kyu;Kim, Kyong-Moo
    • Journal of the Society of Naval Architects of Korea
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    • v.45 no.4
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    • pp.462-467
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    • 2008
  • In this paper, we investigated the design method of mooring system in ultra deep sea and carried out the conceptual design for offshore West Africa oil field in ultra deep sea of 3000 meters. Recently, it was feasible to design and install the offshore floating structures in deep sea of up to 2000 meters. Due to the simplicity, two-point mooring design is fully utilized. Force-excursion curves are throughly examined to find out the feasibility of various combinations of mooring lines. Free length and pretension effects are discussed. It is found that composite materials including synthetic fiber rope may be good solution for ultra deep sea mooring design.

Temporal and Spatial Variations of SST and Ocean Fronts in the Korean Seas by Empirical Orthogonal Function Analysis

  • Yoon, Hong-Joo;Byun, Hye-Kyung;Park , Kwang-Soon
    • Korean Journal of Remote Sensing
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    • v.21 no.3
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    • pp.213-219
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    • 2005
  • In the Korean seas, Sea Surface Temperature (SST) and Thermal ronts (TF) were analyzed temporally and spatially during 8 years from 1993 to 2000 using NOAA/AVHRR MCSST. In the application of EOF analysis for SST, the variance of the 1st mode was 97.6%. Temporal components showed annual variations, and spatial components showed that where it is closer to continents, the SST variations are higher. Temporal components of the 2nd mode presented higher values of 1993, 94 and 95 than those of other years. Although these phenomena were not remarkable, they could be considered ELNI . NO effects to the Korean seas as the time was when ELNI . NO occurred. The Sobel Edge Detection Method (SEDM) delineated four fronts: the Subpolar Front (SPF) separating the northern and southern parts of the East Sea; the Kuroshio Front (KF) in the East China Sea, the South Sea Coastal Front (SSCF) in the South Sea, and the Tidal Front (TDF) in the West Sea. TF generally occurred over steep bathymetry slopes, and spatial components of the 1st mode in SST were bounded within these frontal areas. EOF analysis of SST gradient values revealed the temporal and spatial variations of the TF. The SPF and SSCF were most intense in March and October; the KF was most significant in March and May.

Analysis of Extreme Sea Surface Temperature along the Western Coastal area of Chungnam: Current Status and Future Projections

  • Byoung-Jun Lim;You-Soon Chang
    • Journal of the Korean earth science society
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    • v.44 no.4
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    • pp.255-263
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    • 2023
  • Western coastal area of Chungnam, including Cheonsu Bay and Garorim Bay, has suffered from hot and cold extremes. In this study, the extreme sea surface temperature on the western coast of Chungnam was analyzed using the quantile regression method, which extracts the linear regression values in all quantiles. The regional MOHID (MOdelo HIDrodinâmico) model, with a high resolution on a 1/60° grid, was constructed to reproduce the extreme sea surface temperature. For future prediction, the SSP5-8.5 scenario data of the CMIP6 model were used to simulate sea surface temperature variability. Results showed that the extreme sea surface temperature of Cheonsu Bay in August 2017 was successfully simulated, and this extreme sea surface temperature had a significant negative correlation with the Pacific decadal variability index. As a result of future climate prediction, it was found that an average of 2.9℃ increased during the simulation period of 86 years in the Chungnam west coast and there was a seasonal difference (3.2℃ in summer, 2.4℃ in winter). These seasonal differences indicate an increase in the annual temperature range, suggesting that extreme events may occur more frequently in the future.

VULCANOKARST ON CHEJU ISLAND IN SOUTH KOREA

  • Hong, Shyhwan
    • Journal of the speleological society of Korea
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    • v.41 no.1
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    • pp.3-15
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    • 1994
  • Geographically Cheju Island is located in the southmost part of Korea. Cheju Province, the largest. island in Korea, consists of one major island, Cheju, and other minor islands including Chuja Island. The province is located in around 140 km from Mokpo on the north, about 272 km from Pusan. Tsushima Island of Japan on the northeast, and Shanhai of the China across the East China Sea to the west.(omitted)

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A Study of Long-term Trends of SST in the Korean Seas by Reconstructing Historical Oceanic Data (과거 해양자료 복원을 통한 한반도 주변해역 표층수온의 장기변동 연구)

  • Park, Myung-Hee;Song, Ji-Young;Han, In-Seong;Lee, Joon-Soo
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.7
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    • pp.881-897
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    • 2019
  • We reconstructed and digitized the National Institute of Fisheries Science (NIFS) Serial Oceanographic observations (NSO) and Coastal Oceanographic observations (NCO) data attained prior to 1961 through historical oceanographic observation data rescue projects. Increasing trends of long-term sea surface temperature (SST) were shown from the NSO data of 21 available stations for the past 80 to 92 years. In general agreement with previous research results used in the data of the past 50 years, we calculated the rate of temperature rise. As a result of analyzing the spatial distribution of SST change rate in the Korean of shore region using selected oceanographic data, the West Sea and South Sea showed a higher tendency of temperature rise in the offshore area than in the coastal area. However, unlike the results of previous studies, the East Sea (Gangwon Line and Ulsan Line) showed a lower water temperature rise than the coastal stations. Annual fluctuations of NCO's SST data from 1989 to 1998 for three stations representing the East Sea, South Sea, and West Sea, (Jumunjin, Geomundo and Budo, respectively) revealed that the East Sea showed the highest SST increase for the 10 years. The increases were 1.63 ℃ at Jumunjin, 1.16 ℃ at Geomundo, and 0.79 ℃ at Budo. As a result of the investigation, it can be concluded that SST is repeatedly rising and falling with a period of 3 ~ 6 years. Especially, since the 1980s, most of the stations show positive anomalies of SST. Lastly, to understand ocean_atmosphere interactions, we analyzed the correlations between SST of the NCO stations and air temperature around them and the results were 0.76 for the South Sea (Geomundo), 0.34 for the West Sea (Budo), and 0.32 for the East Sea (Jumunjin) with the highest correlation in the South Sea.