• 한국해양학회지
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• v.19 no.1
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• pp.11-17
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• 1984

The abnormal cooling phenomenon occurred in the coastal areas of East Sea of Korea in summer, 1981 is studied on the basis of the oceanographical data obtained by the National Fisheries University of Pusan, in July, 1981 and by Fisheries Research and Development Agency of Korea during 1961 to 1981 and by Japan Meteorological Agency in 1975 and 1981. Th vertical section of temperature along 130 E showed that the warmer waters more than 10 C occupied at upper layer of about 75m depth in south of 35 30'N the layer changed rapidly thinner as 20m th 30m depth. In the areas of East Sea during 1966 to 1981, the temperature fluctuations at 100m depth ranged greatly in standard deviation from 2 C to 4 C. The temperature anomaly in 1981 was about 1.5 times of the standard deviation and at the upper layer of 150m depth the temperatures became colder by 5 -10 C than average values in August, 1961-1975. The 10 C isotherm at 100m depth in 1981 appeared between 35 and 36 N, shifting southward 20 to 120 miles than mean year. These results showed that the abnormal cooling phenomenon in the areas of East Sea of Korea in summer occurred mose predominantly in 1981 in period from 1966 to 1981

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.216-223
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• 2000

In order to study origin and mixing ratio of surface water masses in the East China Sea (ECS), the South Sea of Korea and the Korea Strait, we use three end-member mixing equation. We use $^{228}$Ra/$^{226}$Ra activity ratio and salinity as two conservative tracer and the Changjiang Water (CW), the Yellow Sea Water (YSW), and the Kuroshio Water (KW) as three end members, Results show that ECS surface water includes all the three end member water, in the order of KW (50-90%), YSW (20-40%) and CW (0-20%) in August 1997. Also, the amount of CW can be approximately estimated by salinity alone. Surface water of the South Sea and the Korea Strait includes very small or almost no CW (below 2% except station 9) in May 1998. Thus in the Korea Strait mixing ratio could be estimated by $^{228}$Ra/$^{226}$Ra activity ratio tracer alone between two end-members, KW and YSW. However, in order to Set more accurate results or in case of rainy season, a mixing equation based on two tracers and three end-members is required.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.15-28
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• 1992

Temporal variations of the path of the East Korea Warm Current(EKWC) which flows northward along the east coast of Korea were analysed to investigate whether the EKWC directly influences the existence of the so-called Warm Core in the Ulreung basin. From the 13 years(1975-1987) data of the Fisheries Research and Development Agency(FRDA), the $10^{\circ}C$ isotherm at the 100m depth and the depth of $2^{\circ}C$ isotherm and the temperature field at the 200m depth were used for identification of the path and the central position of the Warm Core. Sea surface winds computed from the surface pressure charts gave the monthly-averaged wind stress curl over the East Sea which was used for determination of the Sverdrup transport. And the mass transport stream functions were computed by use of the Sverdrup balance. The variations of the path show that the EKWC does not always have a fixed path and fluctuates with time. And the existence of the Warm Core is independent upon the presence of the EKWC even when the EKWC doesn't flow northward along the east coast of Korea. In view of the mass transport stream functions, the influences of the sea surface winds on the branching of the Tsushima Warm Currents and the presence of the EKWC were investigated. The presence of the EKWC may be hindered by the southward flow driven by the sea surface winds when the Tsushima currents are rather weak. A very weak correlation exists between the north-south component of the Sverdrup transport and the position of the Warm Core. However, a small but significant part of the southward transport across the latitudinal line of $38^{\circ}N$ indicates that cold water from the northern part of the East Sea may be driven and be forced to flow beneath the permanent thermocline in such a way that the thermal structure of the Warm Core and its position might be changed.

• Journal of Environmental Science International
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• v.11 no.11
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• pp.1141-1147
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• 2002

Based on the tide gauge data from the Permanent Service for Meau Sea Level (PSMSL) collected at 23 locations in the Korean coast, the long-term sea-level trend was computed using a simple linear regression fit over the recorded length of the monthly mean sea-level data. The computed sea-level trend was also corrected for the vertical land movement due to post glacial rebound(PGR) using the ICE-4G(VM2) model output. It was found that the PGR-corrected sea-level trend near Korea was 2.310 $\pm$ 2.220 mm/yr, which is higher than the global average at 1.0∼2.0mm/yr, as assessed by the Intergovernmental Panel on Climate Change(IPCC). The regional distribution of the long-term sea-level trend near Korea revealed that the South Sea had the largest sea-level rise followed by the West Sea and East Sea, respectively, supporting the results of the previous study by Seo et al. However, due to the relatively short record period and large spatial variability, the sea-level trend from the tide gauge data for the Korean coast could be biased with a steric sea-level rise by the global warming during the 20th century.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.6
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• pp.341-350
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• 1988

The wind stress distribution over the East Sea of Korea was obtained from the shipboard observations of the Fisheries Research and Development Agency along the serial observation lines. These monthly and annual mean wind stress distributions were put into the simplified interface model which describes the latitudinal variations of the upper-layer thickness as function of the curl of the wind stress. The observed variations of the surface, zonally averaged winds indeed caused the upper-layer flow convergent and divergent at the latitudes that produced a tone of thick upper-layer or a deep permanent thermocline and the shallower depth with divergence. Thus, the wind field contributes positively to maintain the almost time-independent distribution of the interface of 'saddle like' feature in north-south direction over the study area.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.842-845
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• 2004

When the concrete structures are in contact with seawater, concentration of chloride for estimating chloride diffusion coefficient can be defined as the chloride concentration of sea water. However, in case the concrete structures, constructed in the seashore, aren't directly in contact with seawater, it is difficult to establish the interface concentration of chloride. In addition, marine concrete structures are greatly affected by salt attack such as rebar corrosion, among the cause of salt attack, airborne sea salt is primary factor. Therefore, in this study, salt attack environment by airborne sea salt was investigated in terms of the distance from seashore at 33 spots, 6 areas in East, West, South coast for 1 year. Results indicated that airborne sea salt is decreased by $y=a{\cdot}x^{-b}$ equation to the distance from seashore.

• Korean Journal of Environment and Ecology
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• v.30 no.1
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• pp.104-109
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• 2016

In Korea, the government has invested the installation of artificial reefs (ARs) which deploying to enhance the restoration of marine environment and productivity on the coastal area at the part of 222,627ha, from 1971 to 2014 for 44 years. The number of ARs are gradually increasing, while their comparison and corelation analysis were not much studied. Therefore, this study is to analyse temporal variation of ARs which composed of concrete named the Horn triangle reefs were deployed at Pohang, Jangkil-ri, a depth of 5 to 7m, in 2003, was monitored 4 times from 2009 to 2011. In results, the biodiversity investigated that the dominant species was Mollusca Omphalius pfeifferi except in 2009. The different species mainly depend on spatial-temporal variation. In this type of study can be used to the R&D, management and government policy of ARs as well improving marine environment.

• Journal of the Korean earth science society
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• v.24 no.4
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• pp.337-345
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• 2003

Surficial sediments from the northern coastal area of Jeju Island, southeastern Yellow Sea (South Sea of Korea) were analyzed for grain-size texture, some geochemical characteristics and clay mineralogy in order to assess their provenance. Rare-earth element compositions and some geochemical discrimination diagrams, especially of Ti/Al, Nb/Al and Rb/Al ratios, were revealed to be useful indices for identifying the origin of sediments. These indices, together with clay mineral compositions, suggest that the coarse-grained sediments originate from the volcanic rocks of Jeju Island, whereas the fine-grained sediments are derived from Chinese rivers, especially the Changjiang River. The oceanic circulation pattern and the physical-chemical properties of seawater in the Yellow and East China seal support the possibility that the fine-pained Changjiang (Yangtze River) sediments can reach the coastal area of Jeju Island (southeastern Yellow Sea).

• Fisheries and Aquatic Sciences
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• v.24 no.7
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• pp.243-259
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• 2021

The spatial and temporal behaviors and fluctuations of the cold water that appeared in the South East Sea and the East Sea coast from 2016 to 2017 were investigated. The water temperature drop was large in the east coast from April to June and the southeast coast from July to September, and the temperature drop period was longer in the southeast coast. The water temperature fluctuated sensitively to the wind direction, and it gradually decreased in the southwest wind but rose as if jumping in the northeast wind. Wind stress and surface water temperature had an inverse correlation, which was larger in Bukhang-Idukseo, and decreased toward the north of Guryongpo. The cold water appeared mainly in Geojedo-Pohang after 1 to 2 days when the southwest wind was strong, but when the wind became weak, it shrank to the Idukseo (Ulgi-Gampo) and extended into the open sea in a tongue shape. Cold water was distributed only in Samcheok-Toseong in mid-May, Idukseo-Guryongpo and Hupo-Jukbyeon-Samcheok from late May to mid-July, and Bukhang-Idukseo in August-September. The intensity of cold water was greatest in mid-August, and the center of cold water descended from the east coast to the southeast coast from spring to summer. The water temperature fluctuation was dominant at the periods of 1 d and 7-21 d. In wavelet spectrum analysis of water temperature and wind, wind speed increase-water temperature decrease showed phase difference of 12 h in 2 d, 18 h in 3 d, 1.5 d in 4-8 d, and 2-3 d in 8-24 d period. The correlation between the two parameters was large in Geojedo and Namhang, Bukhang-Idukseo, Guryongpo-Jukbyeon, and Samcheok-Toseong. Monitoring stations with high correlation in all periods were generally parallel to the monsoon direction.

• Korean Journal of Medicinal Crop Science
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• v.14 no.6
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• pp.347-353
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• 2006

This study was conducted to evaluate the vegetation structure and ordination of the Peucedanum japonicum Thunb. community by the Phytosociological method, floristic composition table on east coast of South Korea. The vegetation of Peucedanum japonicum Thunb. community was classified into 2 communities such as the Aster Spathulifolius community and the calystegia soldanella-Artemisia princeps community. Vegetation of the Peucedanum japonicum Thunb. community with the Aster spathulifolius community was shown southward, whereas vegetation of Peucedanum japonicum Thunb. community with the calystegia soldanella-Artemisia princeps community was shown northward from the base line of Pohang at North latitude of 36" 05'. Accordingly, the Peucedanum japonicum Thunb. community was grown commonly with the Aster spathulifolius community southward of the base line of Pohang, whereas it was grown commonly with the calystegia soldanella-Artemisia princeps community northward on the east coast. All environmental conditions of habitat taken together, the optimum habitat of Peucedanum japonicum Thunb. was at Ulsan geographically and the middle region of sea cliff topography, and was suitable for alkali. sandyloam.