• Journal of Ocean Engineering and Technology
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• v.14 no.3
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• pp.1-10
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• 2000

In order to effective manage the construction, disaster prevention plan and the harbor tranquility control, meteorological and sea-state characteristics around Cheju Island have been analyzed. Using results and damage examples of the port facilities under severe sea conditions, a reasonable construction control plan considering the regional characteristics of the sea-state and winds was proposed. That is, in northern part of Cheju Island, the construction work is affected mainly by the winter storms, while the typhoon mainly affects the southern part port facilities during summer to Autumn. Considering their typical characteristics, it is strongly suggested that the main construction work should be carried out during April to July in the northern part, and it should be made during October to next July in the southern part of the island. A permeable TTP mounded breakwater was constructed to protect severe waves as a temporal structure under the long-term development plan in Sogipo port. The transmission characteristics of the structure was discussed using the experimental results. The results show that the transmission coefficient $K_{t}$ is over 20% of incident waves, which cause many problems in the cargo handling in relation to harbor tranquility. In conclusion, this kind of permeable structure can be used only as a temporal structure for the disaster prevention under the construction process. It causes many problems in harbor tranquility if it is used as a permanent harbor structures.s.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.659-666
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• 2014

Our aim was to compare the community structure of fish in the coast of Wando Island between 2001 and 2013. Using a gape net with wings, we collected 61 taxa, wherein the most dominant species was Engraulis japonicus. The sea temperature in the middle layer of the survey station in 2001 (after June) was obviously higher than that in 2013, which was < $20^{\circ}C$. Except for Thryssa kammalensis in 2013, the log transformed individuals of seven dominant species, selected using a SIMPER (similarity-percentages procedure) analysis, decreased. Decreases in the individuals of Gobiidae spp., the warm-water species Trichiurus japonicus and Conger myriaster, and the migratory species Syngnathus schlegeli, Setipinna taty and Sardinella zunasi, which arrive in the southern coastal waters of Korea during summer-autumn, could be due to decreasing sea temperature in 2013. Thus, fish species diversity, estimated from rarefaction and k-dominance curves, declined in the coastal waters of Wando Island from 2001 to 2013, resulting in a significant difference in fish community structure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.776-782
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• 2015

We examined the community structure of fish off the coast of Jindo Island in response to a cold water appearance in the southwestern sea of Korea each August between 2013–2015. Using a gape net with wings, we collected 31 taxa during the study period, wherein the most dominant species was Engraulis japonicus. Collichthys lucidus and Neosalanx andersoni, which are mainly distributed in the western sea of Korea, increased in abundance and were dominant in August 2013, possibly due to the apparent intrusion of cold water (< 19°C) from offshore into the coastal waters of Jindo Island. Meanwhile, Scomberomorus niphonius and Sardinella zunasi, which are known as warmwater migratory species, increased in abundance and were dominant in August 2015, likely influenced by the warmer water (> 20°C) at the coast, which resulted in a noticeable lessening of the cold water in the study area. However, no significant differences were observed in fish community structure in the month of August between 2013–1015. This implies that the small-scale spatial and temporal variations in the cold water had limited effects on the fish community structure, even though the abundances of several dominant species varied in the coastal waters.

• 한국해양학회지
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• v.13 no.1
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• pp.1-8
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• 1978

A seismic reflection Survey was carried out in the offshere area between Geoje Island and Namhae Island, utilizing the echosounder with the frequency 28KHz and thd Uniboom with the filter band 800∼2000Hz. The results show the submarine topography, sedimentary layer structure and the depth distribution of the base rock. The water depth of the sea in the survey area is less than 80m; up to 40m contour line the sea bottom surface has a slight dip(about 1/1000), while in the zone deeper than 40m the bottom topography has a irregular relief. The thickness of the whole sedimentary deposit is about 20∼70m and divided into 3 layers: Upper layer(A layer) with horizontal laminae, intermediate layer(B layer) with cross-bedding and groove structure, and lower layer(C layer) not showing any sedimentary structure on the seismic reflection profile. The surface of the base rock is deeper gradually in the south-eastern part of the survey area and extends to 140m depth. The vertical sediments sequences, composed of B layer and A layer, show the type of transgressive sequences. It is interpreted that B layer was formed at one period when the sea level was lower 40∼60 than the present and ince then, following the rising of the sea level, A layer was deposited.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.4
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• pp.45-71
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• 1991

The landscape systems in Korean island settlements can be recognized as results of ingabitants' ecological adptation to the isolated environment with the limited natural resources. Both the fishery dominant industry in island society and ecological nature of its environments seem to have influenced on inhabitants' environmental cognition as well as the physical landscape of island villages such as its location, spatial pattern in each village, housing form and so on. This study was done mainly by both refering to the related documents and direct observations in case study areas, and results of the study can be summarized as follows. 1. In general, the landscape of an individual island seems to take more innate characteristics of island's own, corresponding to the degree of isolation from mainland. That is, while the landscape of island in neighboring waters takes both inland-like and island-innate landscape character at the same time, the one in the open sea far from land takes more innate landscape character of all island's own in the aspects of village location, land use and housing density etc. 2. The convex landform of most islands brings about more centrifugal village allocation than centripetal allocation in most inland villages. And thus most villages in each island face extremely diverse directions different from the south facing preference in most inland rural villages. 3. Most island villages tend to be located along the ecologically transitional strip between land and sea, so called 'line of life', rather than between hilly slope and flat land as being in most inland village locations. So they are located with marine ecology bounded fishing ground ahead and land ecology bounded agricultural site at the back of them. 4. The settlement pattern of the island fishing villages shows more compact spatial structure than that of inland agricultural villages, due to the absolute limits of usable land resources and the adaptation to the marine environment with severe sea winds and waves or for the easy accessability to the fishing grounds. And also the managerial patterns of public owned sea weed catching ground, which take each family as the unit of usership rather than an individual, seem to make the villagescape more compact and the size of Individual residence smaller than that of inland agricultural village. 5. The folk shrine('Dand') systems, in persrective of villagescape, represent innate environmental cognition of island inhabitants above all other cultural landscape elements in the island. Usually the kinds and the meanings of island's communal shrine and its allocative patternsin island villagescape are composed of set with binary opposition, for example 'Upper shrine(representing 'earth', 'mountain' or 'fire')' and 'Lower Shrine(representing 'sea', 'dragon' or 'water') are those. They are usually located at contrary positions in villagescape each other. That is, they are located at 'the virtical center or visual terminus(Upper shrine at hillside behind the village)' and 'the border or entrance(Lower Shrine at seashore in front of the village)'. Each of these shirines' divinity coincides with each subsystem of island's natural eco-system(earth sphere vs marine sphere) and they also contribute to ecological conservation, bonded with the 'Sacred Forest(usually with another function of windbreak)' or 'Sacred Natural Fountain' nearby them, which are representatives of island's natural resources.

• 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.

• Animal Systematics, Evolution and Diversity
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• v.36 no.4
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• pp.330-335
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• 2020

The sea spider genus Cilunculus Loman, 1908 comprises 33 species having short chelifores, separate lateral processes, and a hood structure on the cephalic segment. A pycnogonid species, Cilunculus armatus(Böhm, 1879), was collected from Baekdo Island and Chujado Island, Korea. This species is characterized by having a hood structure on the cephalic segment, separate lateral processes, a low ocular tubercle without eyes, and 3-segmented chelifores. In the examined material, chela shape, arrangement of compound spines on strigilis, and number of heel spines at propodus were different from the previous literatures. Here, we examined C. armatus collected in Korean waters and provided illustrations and pictures in detail.

• Geophysics and Geophysical Exploration
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• v.11 no.4
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• pp.286-301
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• 2008

When magnetotelluric (MT) data are obtained in vicinity of the coast, the sea can distort observed MT responses, especially those of deep part of subsurface. We introduce an iterative method to correct the sea effect, based on the previous topographic correction method which removes the distortions due to topographic changes in seafloor MT data. The method first corrects the sea effect in observed MT impedance, and then inverts corrected responses in a model space without the sea. Due to mutual coupling between sea and subsurface structure, the correction and inversion steps are iterated until changes in each result become negligible. The method is validated for 1-D and 2-D structure using synthetic MT data produced by 3-D forward modeling including surrounding seas. In all cases, the method closely recovers the given structure after a few iterations. To test the applicability of the proposed method to field data, we generate synthetic MT data for the Jeju Island whose 1-D conductivity structure is well known, using 3-D forward modeling. The distortions due to the surrounding sea start to appear below the frequency about 1 Hz, and are relatively severe in the electrical field perpendicular to the coastline because of the location of the observation sites. The proposed method successfully eliminates the sea effect after three iterations, and both 1-D and 2-D inversion of corrected responses closely recover the given subsurface structure of the Jeju Island model.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.354-365
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• 2019

Megabenthos samples were collected using 10-min trawls towed at 17 stations from 2015 to 2016. The dominant species (>1% of the total density) were Stegophiura sterea (10.4%) and two subtropical species, Mactrinula dolabrata (9.0%) and Acila divaricate (8.3%), respectively. The community structure of the megabenthos fell into four groups: the southeast, the southernmost region off Jeju Island, the frontal zone of the South Sea with C3, and a diagonal area from the south coast to the western side of Jeju Island. The total numbers of species, diversity, density and biomass were higher in the C3 region of the South Sea. Environmental factor analysis showed that differences in the megabenthos community were related to depth, gravel contents, and sorting value (${\sigma}$). These results indicate that changes in the marine environmental conditions in the South Sea of Korea affect the megabenthos species' composition and diversity.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.3
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• pp.327-339
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• 2003

During the winter in February 1998, January and April 1999, interdisciplinary research was conducted in a large area including the South Sea of Korea and northern East China Sea to examine distribution and structure. Water masses identified from the observed data are Warm Water originated from Tsushima Warm Current, Yellow Sea Cold Water (Northern or Central Cold Water) and Korean Southern Sea Cold Water. In the southern Yellow Sea, Warm Water originated from Tsushima Warm Current, flowing into the Cheju Strait after turning around the western Cheju Island, makes a front of '┍' shape, which is bounded by the Yellow Sea Central Cold Water in the southern part of Daeheuksan Island and by the Yellow Sea Northern Cold Water in the eastern part of the Yangtze Bank. This front changes its corner shape and position with strength of the warm water extension toward northwestern Yellow Sea. The position and structure of the fronts off the southwestern tip of the Korean peninsular and near the Yangtze Bank varies with observation period. In the front in the South Sea of Korea, cold coastal water which if formed independently due to local cooling, ,sinks along the sloping bottom. We explained the processes of variations in the distribution and structure of these winter fronts in terms of up-wind and down-wind flow by the seasonal monsoon, heat budget through the sea surface and density difference across the fronts.