• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.3
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• pp.255-269
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• 2023

Surface water temperature of a bay (from the south to the north) increases in spring and summer, but decreases in autumn and winter. Due to shallow water depth, freshwater outflow, and weak current, the water temperature in the central to northern part of the bay is greatly affected by the land coast and air temperature, with large fluctuations. Water temperature variations are large in the north-east coast of the bay, but small in the south-west coast. The difference between water temperature and air temperature is greater in winter and in the south-central part of the bay than that in the north to the eastern coast of the bay where sea dykes are located. As the bay goes from south to north, the range of water temperature fluctuation and the phase show increases. When fresh water is released from the sea dike, the surrounding water temperature decreases and then rises, or rises and then falls. The first mode of empirical orthogonal function (EOF) represents seasonal variation of water temperature. The second mode represents the variability of water temperature gradient in east-west and north-south directions of the bay. In the first mode, the maximum and the minimum are shown in autumn and summer, respectively, consistent with seasonal distribution of surface water temperature variance. In the second mode, phases of the coast of Seosan~Boryeong and the east coast of Anmyeon Island are opposite to each other, bordering the center of the deep bay. Periodic fluctuation of the first mode time coefficient dominates in the one-day and half-day cycle. Its daily fluctuation pattern is similar to air temperature variation. Sea conditions and topographical characteristics excluding air temperature are factors contributing to the variation of the second mode time coefficient.

• Acta Via Serica
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• v.3 no.2
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• pp.23-48
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• 2018

The Silk Road usually implies a network of trade and communications that stretched from east to west and connected China and the countries of the Far East via Central Asia and the Middle East to the eastern Mediterranean, or through the northern coast of the Caspian Sea and the Volga basin to the Black Sea coast. However, at certain historical stages, a network of maritime and overland routes stretching from north to south, commonly called the Volga-Caspian trade route, also played a significant role in international trade and cultural contacts. The geopolitical realities of the early Middle Ages relating to the relationship of Byzantium, the Sassanid Empire, and the West Turkic Khaganate, the advance of the Arab Caliphate to the north, the spread of Islam in the Volga region, the glories and fall of the Khazar State, and the Scandinavian campaigns in the Caucasus, closely intertwined with the history of transport and communications connecting the north and south through the Volga-Caspian route. In a later era, the interests of the Mongolian Uluses, and then the political and economic aspirations of the Ottoman Empire, the Safavid State, and Russia, collided or combined on these routes. The article discusses trade contacts existing between the north and the south in the 15th and first half of the 17th century along the routes on the western coast of the Caspian Sea.

• 한국해양학회지
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• v.16 no.1
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• pp.12-23
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• 1981

A numerical experiment is made in order to clarify the mechanism of the upwelling phenomenon along the coast near the poleward edge of the western boundary current. The possibility of the upwelling is suggested from the analysis of the observational data in the east of Honshu, Japan, and in the south eastern coast of Korean Peninsula. This upwelling phenomenon is very deep and can be traced to the bottom layer. The upwelling phenomenon seems to be a general oceanic feature which characterizes the region along the west coast near the poleward edge of the western boundary current. This experiment is simulating the oceanic condition of the transition region between Kuroshio front and the Oyashio front in the east of Honshu, Japan. The possible explanations of the causes of the upwelling are as follows;In the interior of the modeled ocean the cold heavy water supplied from the north and the warm light water from the south make the north-south gradient of the pressure field and accelerate the eastward current to produce the h-orizontal divergence feld near the west coast. The divergence is compensated by the upwelling near the separation region. Another one is that the upwell-ed cold water strengthen constantly the pressure gradient which is balanced by the northward current and is weakened by the horizontal diffusion.

• Journal of Ecology and Environment
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• v.42 no.1
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• pp.12-19
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• 2018

Background: The objective of this study was to determine the relationship between soil environmental factors and halophyte distribution in the west coast of South Korea. Soils of our study sites were categorized into two groups: salt marsh and estuary marsh. Results: Salinity was higher in the salt marsh group than that in the estuary marsh group. However, total nitrogen, silt, and clay contents were higher in the estuary marsh group than those in the salt marsh group. Although altitude had a wider range in the salt marsh group, the mean altitude was higher in the estuary marsh group than that in the salt marsh group. Annual halophytes of seed propagation species were distributed parallel to the coast line on salt marsh. Higher coverage of vegetation was found in the area closer to the coast line. Plant density was higher near dead parental plants in estuary marsh, showing less difference in area that was more distant from the coast line. Conclusions: Results of canonical correspondence analysis (CCA) for vegetation distribution and sediment environmental factors and germination analysis in the coast line showed significant relationship with halophyte distribution. Therefore, they can be used as an indicator of coastal plant movement due to sea level rise.

• Animal Systematics, Evolution and Diversity
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• v.28 no.1
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• pp.12-19
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• 2012

A cyclopoid species from several salt marshes and estuaries on the west coast of South Korea were identified as Halicyclops continentalis Ueda and Nagai, 2009, recently described from Ariake Bay at northwestern Kyushu, Japan. Detailed examination on the Korean specimens justifies Ueda and Nagai's proposition that the H. sinensis sensu Tai and Chen, 1979 formerly known from the Chinese coast of the Yellow Sea should be identical to H. continentalis. Furthermore, this report reinforces their assumption on the geographical distribution of H. continentalis, that is, the Ariake Bay population is a continental relict of the East Asia continent. Herein, a redescription of the species is provided on the basis of the Korean specimens, with a comment on the morphological comparison among three populations around the Yellow Sea.

• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.349-355
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• 2023

This study surveyed the island located in Sinan-gun and Wando-gun four times, once per season from September 2020 to November 2021 in order to understand the distribution of waterbirds on the island of the southwest coast. As a result of the investigation, a total of waterbirds of 7 orders, 12 families of 50 species, and 3,680 individuals were identified. By taxon, the largest number of species were identified as 11 species of waders, and the number of ducks was the largest with 2,035 individuals. In Bigeum-do Island, where forests are distributed less, the proportion of farmland is large, and tidal flats are widely distributed, the largest number of species and individuals of herons and waders were identified. Ducks and gulls have also been identified in large numbers of individuals in Bigeum-do Island. Most of them are forests and farmland, and the largest number of species and individuals of ducks have been identified in Pyeongil-do Island, where the coast is deep. In addition, Nodae-do Island, Sobyeongpung-do, and Daebyeongpung-do Island with monotonous habitats have been identified with fewer species and individuals. As a result, We learned that various types of waterbirds lived in islands with various habitats, and that the preferred habitat was different depending on the characteristics of the taxon group. By season, the largest number of species was identified as 35 in autumn, and the largest number of individuals was identified as 1,681 in winter. Although most of the seasonally identified waterbirds were winter birds, the largest number of species were identified in autumn, and most of the confirmed waterbird migration were identified in the autumn, indicating that waterbirds used the west-south coast islands as an intermediate stopover while traveling.

• Journal of the Korean GEO-environmental Society
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• v.16 no.7
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• pp.15-22
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• 2015

This study gives the characteristics of sedimentation-consolidation and surface strength for dredging and landfill areas in each coast. For the analysis of the sedimentation-consolidation characteristics, the column tests were performed and the results were compared with existing various literatures and design reports for dredged soil disposal. The surface strength of landfill soils of west and south coast were investigated by using the portable cone tester. As a results of analysis, the coefficient of sedimentation-consolidation on south coastal dredging soils is more sensitive with variation of initial water contents than on the west coastal dredging soils. And the surface strength of the dredging landfills is a higher in the west coast than in the south coast. Finally, the results of this study will be utilized as a basis data for analysis and design in the field of dredging and landfill.

• Wind and Structures
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• v.13 no.1
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• pp.37-55
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• 2010

In this paper South Africa is divided into strong wind climate zones, which indicate the main sources of annual maximum wind gusts. By the analysis of wind gust data of 94 weather stations, which had continuous climate time series of 10 years or longer, six sources, or strong-wind producing mechanisms, could be identified and zoned accordingly. The two primary causes of strong wind gusts are thunderstorm activity and extratropical low pressure systems, which are associated with the passage of cold fronts over the southern African subcontinent. Over the eastern and central interior of South Africa annual maximum wind gusts are usually caused by thunderstorm gust fronts during summer, while in the western and southern interior extratropical cyclones play the most dominant role. Along the coast and adjacent interior annual extreme gusts are usually caused by extratropical cyclones. Four secondary sources of strong winds are the ridging of the quasi-stationary Atlantic and Indian Ocean high pressure systems over the subcontinent, surface troughs to the west in the interior with strong ridging from the east, convergence from the interior towards isolated low pressure systems or deep coastal low pressure systems, and deep surface troughs on the West Coast.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.6
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• pp.276-280
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• 2001

This paper presents the result of a study on the distribution characteristics of salt contaminants in the west coast region, from Inchon to Yearsoo, of South Korea. To evaluate the distribution characteristics of salt contaminants, we had measured the equivalent salt deposit density(ESDD) with brush wiping method for thirteen month(from May 1999 to June 2000). Under the consideration on the measuring interval and method, normalization method was applied for the ESDD data. Besides the measurement, the chemical analysis (chromatography) was carried to investigate the relationship, between the electrical property and the amount of specific ingredient, such as sodium, magnesium and chloride. From the result, we could get the representative value of contamination for each site and distribution characteristics of salt contaminants with the distance from sea in the west coast.

• Journal of Climate Change Research
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• v.9 no.4
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• pp.369-376
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• 2018

Korea is surrounded by the West Sea, the South Sea, and the East Sea. There are various points at which large and small rivers flow into the sea, and areas where these rivers meet the coast are vulnerable to disasters. Thus, it is necessary to study disaster prevention techniques based on coastal characteristics and the pattern of disasters. In this study, we analyzed the risk factors of disaster districts analyzed in comprehensive plans for the reduction of damage to coastal cities from storms and floods. As a result of standardization, four factors (tide level, intensive rainfall & typhoon, wave, and tsunami) were identified. Intensive rainfall & typhoon occurred along the West Sea, the South Sea, and the East Sea coast. Factors that should be considered to influence disasters are tide level for the West Sea, tsunami and tide level for the South Sea, and wave in the East Sea. In addition, disaster prevention techniques to address these factors are presented, focusing on domestic and overseas cases.