• Title/Summary/Keyword: middle east coast of Korea

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Formative Age of Coastal Terraces and Uplift Rate in the East Coast of South Korea (우리나라 동해안의 해안단구 형성시기와 융기율)

  • Park, Chung-Sun;Kihm, You Hong;Nahm, Wook-Hyun;Lee, Gwang-Ryul
    • Journal of The Geomorphological Association of Korea
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    • v.24 no.4
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    • pp.43-55
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    • 2017
  • This study tries to examine papers on coastal terrace in the East Coast of South Korea and to summarize formative age and elevation of the terrace. Spatial and temporal variations of uplift rate in the Coast based on absolute age published are also reviewed. The terrace in the middle part in the Coast from Goseong to Samcheok distributes in an elevation of 10-20 m and its formative age is MIS 5a. The terraces during MIS 5e and 7 develop on an elevation of 20-35 m and 60-80 m, respectively. The mid-southern part in the Coast from Uljin to Yeongil Bay has the terraces with elevations of 10-25 m and 25-45 m and their ages are MIS 5a or 5c and 5e, respectively. The terraces with elevations of 10-25 m and 30-45 m correspond to MIS 5a and 5e, respectively, in the southern part in the Coast from Homigot to Busan. Assuming that elevation of sea level during the formation of each terrace is the same as in the present time, uplift rates in the Coast range from 0.05 to 1.36 m/ky with an average of approximately 0.33 m/ky. The highest and lowest rates since MIS 5 are found in the Gyeongju (approximately 0.39 m/ky) and Pohang (approximately 0.19 m/ky) areas. With a consideration of elevation of sea level at that time, however, the middle, midsouthern and southern parts in the Coast show uplift rates of 0.16-0.28 m/ky, 0.20-0.36 m/ky and 0.24- 0.36 m/ky since MIS 5, respectively, suggesting that the southern part in the Coast has experienced relatively higher uplift rate.

A study on the distribution and composition of marine floating debris in the middle part of East Sea, Korea (동해중부해역에 있어서 부유성 해양 폐기물의 분포와 조성)

  • Jo, Hyeon-Jeong;Kwon, O-Bin;Jeong, Sun-Beom
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.41 no.4
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    • pp.306-315
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    • 2005
  • The distribution and composition of marine floating debris were recorded from a training ship 'Kyeongyang' of Gangwon Provincial University at May 19-29, 2004 and Aug.24-31, 2004. The sampled area is the middle part of East Sea of Korea(the coast of Gangwondo and region of Ulleung island and Tokdo), divided into 27 unit segments on survey areas. Debris fabrication materials were categorized with 6 items using the following; styrofoam, paper & cardboard, net & rope, vinyl & plastic, floating metal & glass, man-made or natural wood. From the investigation on May,2004, total numbers of marine floating debris in the middle part of the East Sea of Korea was 996 individuals. The No. 1 and No. 2 unit segment located at south-west region of Ulleung Island showed higher density than others. The styrofoam and vinyl & plastic accounted for 72.8% of all debris fabrication materials. From the investigation on August, 2004, total numbers of marine floating debris in the coast of the Gangwondo of Korea was 2,473 individuals. The No. 13 and No. 14 unit segment located at the vicinity of Samcheok showed higher density than others. The styrofoam and vinyl & plastic amounted to 76.1%. In the coast of the Gangwondo, the vinyl & plastic showed the highest density of 6 items were 41.3% and 68.0% on May and August, respectively. The total numbers of marine floating debris on May and August were 3,399 individuals. Vinyl & plastic accounted for 59.4%(2,019 ind.) among all debris, next styrofoam 15.8%(537 ind.) and wood 11.2%(379 ind.).

Lightning activity in summer monsoon precipitation over Korean peninsula

  • Kar, S.K.;Ha, Kyung-Ja
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.366-366
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    • 2002
  • Cloud-to ground lightning and total precipitation over Korean peninsula during the summer monsoon season are studied extensively with a special emphasis on the characteristics of convective precipitation. Ten years (1988-1997) lightning and rainfall data and a temporal and spatial scale of one month and 10$^2$ km$^2$ respectively are used to calculate the monthly number of CG lightning flash count. Monsoonal convective activity is higher over the west coast with maxima at two different regions, one in the northern part which increases nortwestward and the other is at the middle west coast of Korea increasing towards the west coast. East coast represents the minimum value of monsoonal convective activity. In the east coast of Korean peninsula, particularly in the region east of Tae-back mountain, the value of Rain yield, (which is defined as the ratio of total precipitation to CG flash count over a common area), is maximum with an average value of 3$\times$10$^{8}$ kg fl$^{-1}$, while the minimum value of rain yield is occurred in the west of Tae-back mountain, with an average value of 0.8$\times$10$^{8}$ kg fl$^{-1}$. Results show in the west coast stations, nearly 82% of the total rainfall is convective in nature, at the middle of the peninsula 53% of the total rain is convective while in the east coast stations 46% contribution from the convective rain is seen. Kanghwa receives the maximum convective rain while at Ulsan the convective rain is minimum. Correlation coefficient between the total precipitation and CG lightning during the summer monsoon season is 0.54.

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Uplift Rate Map and Distribution of Uplift Rate in the East Coast of the Korean Peninsula (동해안의 융기율도와 융기율 분포)

  • Lee, Gwang-Ryul;Park, Chung-Sun
    • Journal of The Geomorphological Association of Korea
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    • v.27 no.1
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    • pp.47-60
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    • 2020
  • This study tried to produce an uplift rate map and reveal the spatial distribution of the rate with topographical characteristics and absolute ages on marine terrace in the East Coast of the Korean Peninsula. Based on a total of 57 ages at 26 sites from previous study and 13 ages at 13 sites from this study, the coast showed the rates ranging from 0.145 m/ka to 0.410m/ka with an average of 0.258 m/ka. The highest and lowest rates were found from the Jeongdongjin area in Gangneung and the Goraebul area in Yeongdeok, respectively. However, some areas in the coast showed large differences in the rate among the sites. In addition, areas with only 1 age were also found, indicative of low reliability. This study suggests that a more reliable and precise interpretation on the rate can be made with more ages identified, especially in Goseong to northern part of Gangneung, middle and southern parts of Samcheok and Yeongdeok, southern part of Pohang to northern part of Gyeongju, and Ulsan.

A Numerical Study of Atmospheric Pollutant Dispersionon over South Korea on Sunny Summer Days (남한 지역에서 여름철 맑은 날의 대기 오염물 확산에 대한 수치적 연구)

  • 이태영;김승범
    • Journal of Environmental Science International
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    • v.5 no.4
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    • pp.411-427
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    • 1996
  • A Lagrangian dispersion model has been developed to study the transport of atmospheric pollutants over the southern Korean peninsula on sunny summer days. A mesoscale atmospheric model has been employed to provide the wind fields and information for turbulent diffusion for the calculation of trajectories using a conditioned particle technique. The model has been applied to the simulation of the transport of atmospheric pollutants emitted from five sources in the coastal locations under various synoptic scale winds. Under calm synoptic scale condition, the particles emitted during daytime are mixed vertically and transported toward inland by sea-breeze, according to the model simulation. The particles are then transported upward at she sea-breeze front or by the upward motion over the mountain, and some particles show tendency of returning toward the coast by the return flow of the sea-breeze circulation. The particles are found to remain over the peninsula throughout the integration period under calm synoptic scale condition. When there is westerly synoptic scale winds the particles emitted in the west coast can reach the east coast within a day of faster depending on the speed. With a synoptic scale southerly wind of 5 m/s, most of the particles from the fine sources are advected toward inland during daytime. During nighttime, significant portion of particles released in the west coast remains over the land, while most particles released in the east coast move toward the sea to the east of the middle peninsula.

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Dietary Habitats of Spinyhead Sculpin Dasycottus setiger in the Coastal Waters of the East Sea, Korea (동해 연안에 출현하는 고무꺽정이(Dasycottus setiger)의 섭식생태)

  • Park, Joo Myun;Jung, Hae Kun;Kim, Beon Sik;Jung, Young Woo;Lee, Chung Il
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.55 no.3
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    • pp.345-352
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    • 2022
  • In this study, the dietary habits of the spinyhead sculpin Dasycottus setiger were investigated based on 156 specimens collected seasonally between May 2018 and February 2019 from the East Sea off the Korean coast. In terms of the weight contribution (%W), the main food items of the spinyhead sculpin were found to be teleosts (33.5%), followed by carid shrimps (13.8%), amphipods (13.3%), cephalopods (12.0%), and polychaetes (7.1%). Dietary analyses based on the weight contribution of different prey taxa in the diet of the spinyhead sculpin revealed considerable variation in the dietary composition in terms of the sampling region and fish size implying intra-specific dietary segregation. The spinyhead sculpin showed a size-related trends in dietary shift from amphipods to carid shrimps and teleosts in northern region, and from carid shrimps and mysids to teleosts and cephalopods in middle eastern coast. Multivariate analyses of dietary changes revealed that the dietary composition of spinyhead sculpin is significantly associated with the sampling site, but not the fish size. Amphipods contributed more to the diets of the northern population, while mysids typified the diets of spinyhead scuplin inhabiting the middle eastern coast, indicating differences in available food resources between the two study regions.

Seasonal and Interannual Variability of the North Korean Cold Current in the East Sea Reanalysis Data (동해 재분석 자료에 나타난 북한한류의 계절 및 경년변동성)

  • Kim, Young-Ho;Min, Hong-Sik
    • Ocean and Polar Research
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    • v.30 no.1
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    • pp.21-31
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    • 2008
  • Analyzing the results of East Sea Regional Ocean Model using a 3-dimensional variational data assimilation scheme, we investigated spatial and temporal variability of the North Korean Cold Current (NKCC) in the East Sea. The climatological monthly mean transport of the NKCC clearly shows seasonal variation of the NKCC within the range of about 0.35 Sv ($=0^6m^3/s$), which increases from its minimum (about 0.45 Sv) through December-January to March, decreases during March and May, and then increases again to the maximum (about 0.8 Sv) in August-September. The volume transport of the NKCC shows interannual variation of the NKCC with the range of about 1.0 Sv that is larger than seasonal variation. The southward current of the NKCC appears often not only in summer but in winter as well. The width of the NKCC is about 35 km near the Korean coast and its core is located under the East Korea Warm Current. The North Korean Cold Water (NKCW), characterized by low salinity and low temperature, is located both under the Tsushima Warm Water and in the western side of the maximum southward current of the NKCC that means the NKCC advects the NKCW southward along the Korean coast. It is revealed that the intermediate low salinity water, formed off the Vladivostok in winter, flows southward to the south of $37^{\circ}N$ through $2{\sim}3$ paths; one path along the Korean coast, another one along $132^{\circ}E$, and the middle path along $130^{\circ}E$. The path of the intermediate low salinity varies with years. The reanalysis fields suggest that the NKCW is advected through the paths along the Korean coast and along $130^{\circ}E$.

Temporal and Spatial Variations in the Wave Energy Potential of the East Coastal Seas of Korea (동해 연안 파력 부존량의 시간적 및 공간적인 변동 양상)

  • Jeong, Weon Mu;Cho, Hongyeon;Oh, Sang Ho;Kim, Sang Ik
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.25 no.5
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    • pp.311-316
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    • 2013
  • In this study, the wave energy potential (WEP) was evaluated using the wave data measured at nine stations along the Korean east coast and compared with the results of previous studies. Along the Korean east coast, seasonal variations in the WEP were around 6.4 kW/m in winter and 1.2 kW/m in summer, greater than spatial variations of 2.5~4.3 kW/m. In most stations, the wave power during June to July were shown to be smallest. The estimated annual average WEP was greatest in the Mukho and Jukbyeon stations located in the middle of the Korean east coast at around 4.3 kW/m, and smallest in the Jinha station at around 2.5 kW/m. The results found using the previous hindcast data showed WEP having a tendency to decrease from south to north. However, in this study, the WEP showed a tendency of being greatest in the middle of the Korean east coast and decreasing in both north and south directions.

Vegetation Structure of Peucedanum japonicum Thunb. Community in East Seaside of South Korea (우리나라 동해변 식방풍 군락의 식생구조)

  • Shin, Dong-Il;Song, Hong-Seon;Yoon, Seong-Tak;Kim, Seong-Min
    • 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.

Igneous Activity in Ogcheon Geosynclinal Zone, Korea -with Special Reference to the Igneous Activity in its Northeastern Part- (옥천대(沃川帶)에서의 화성활동(火成活動) -특(特)히 옥천대동북부(沃川帶東北部)에서의 화성활동(火成活動)-)

  • Lee, Dai Sung;Kim, Yong Jun
    • Economic and Environmental Geology
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    • v.18 no.1
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    • pp.23-39
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    • 1985
  • The northeastern part of Ogcheon zone which consisted mainly of Cambro-Ordovician arenaceous, argillaceous and calcareous formations and Carboni-Triassic arenaceous and argillaceous formations is delineated as the eastern mass of a thrust fault along Choongju-Moongyong-Cheongsan in the middle of the zone. The present study proposes a geotectonic line, Imgye-Samchog fault(see, figure 1) which divides the northeastern part into two blocks, Hambacksan block in the west and East coast block in the east. The igneous rocks in the Hambacksan block ranging from granite to gabbro are distributed in a symmetrical zones parallel to general direction of Ogcheon zone as follows (Fig. 2 and Table 2). Southeast igneous rock zone: it aligns Jurassic granites in its south and Precambrian leucocratic granites in its north. Central igneous rock zone: it aligns Cretaceous granites in its south and Jurassic granites, and some of diorite and gabbro in its north. Northwest igneous rock zone: aligns Jurassic granites in its south and huge batholithic granodiorite in its north. The distribution of the igneous rocks in the East coast block shows an entirely different features from those of Hanbacksan block. In the southern part of the block they assemble in a narrow area ranging in age from Early Proterozoic, through Middle to Late Proterozoic, Devonian, Jurassic, Cretaceous to Tertiary, whereas, the igneous rocks in the northern part of the block gathered to a restricted area, in ages of Middle Proterozoic and Cretaceous. The assemblage of the igneous rocks in the studied area shows a compositionally restricted, mixed S-type and I-type granites, $^{87}Sr/^{86}Sr$ > 0.706, rare volcanics and shortening with upright folding. These lithologic and structural features suggest that the igneous activity in this part related intimately to Hercynotype Orogeny of Pitcher(1979). Chronological episodes of igneous activity from Early Proterozoic to Early Tertiary in the northeastern part are figured.

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