• Title/Summary/Keyword: Anmyeondo

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Analysis of Sedimentary Environment and Micro-Landform Changes Afterthe Construction of Artificial Structuresin the Tidal Flat of Anmyeondo Gagyeongju, Western Coast of Korea (인공구조물 건설 후 안면도 가경주 간석지의 퇴적환경 및 미지형변화 분석)

  • JANG, Dong-Ho;Ryu, Ju-Hyun
    • Journal of The Geomorphological Association of Korea
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    • v.25 no.1
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    • pp.31-45
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    • 2018
  • This study investigated the characteristics of sedimentary environment changes across a tidal flat in Gagyeongju of Anmyeondo Island. We performed a spatio-temporal analysis on the grain sizes composition of sediments and micro-landform changes during the winter from 2013 to 2016. The results showed that erosion was a dominant processthroughout the study flat, reducing the surface elevation even by 1 m around the upper sand flat. As a consequence, headlands have formed in the entire region of Gagyeongju village. In addition, erosion quickly progressed along the low-lying subtidal zone and tide way and, in contrast, sedimentation progressed in the mid-elevation tidal flat. We posit that a jetty, which had been constructed as a pier facility on the eastern part of the study area, interfered with the flow of tidal current, thereby enhancing these erosional processes. This is because such interference can block the supply of fine-textured sediments from the nearby Cheonsu Bay and therefore reduce surface elevation. According to the surface sediment analysis, the sediments were categorized into 7 sedimentary facies, and generally displayed a high ratio of silt and clay. The result of time-series analysis (2012-2013) showed that the sediments on the tidal flat became fine-grained, and that sorting became worse. However, the sediments on the subtidal zone, embayment and along inside of the jetty tended to be coarse-grained. In conclusion, the tidal flat microlandform change in the study area was caused by a disruption in the seawater circulation due to the jittery construction within the tidal flat, which had a direct effect on erosional and sedimentary environment processes.

GEOSTATISTICAL INTEGRATION OF HIGH-RESOLUTION REMOTE SENSING DATA IN SPATIAL ESTIMATION OF GRAIN SIZE

  • Park, No-Wook;Chi, Kwang-Hoon;Jang, Dong-Ho
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.406-408
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    • 2006
  • Various geological thematic maps such as grain size or ground water level maps have been generated by interpolating sparsely sampled ground survey data. When there are sampled data at a limited number of locations, to use secondary information which is correlated to primary variable can help us to estimate the attribute values of the primary variable at unsampled locations. This paper applies two multivariate geostatistical algorithms to integrate remote sensing imagery with sparsely sampled ground survey data for spatial estimation of grain size: simple kriging with local means and kriging with an external drift. High-resolution IKONOS imagery which is well correlated with the grain size is used as secondary information. The algorithms are evaluated from a case study with grain size observations measured at 53 locations in the Baramarae beach of Anmyeondo, Korea. Cross validation based on a one-leave-out approach is used to compare the estimation performance of the two multivariate geostatistical algorithms with that of traditional ordinary kriging.

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Classification by Erosion Shapes and Estimation of Sea-cliff Erosion Rates through Field Survey in Dundu-ri, Anmyeondo in Korea's Western Coast (현장 조사를 통한 안면도 둔두리 해식애의 침식율 산정 및 침식형태 분류)

  • KIM, Jang-soo;JANG, Dong-Ho
    • Journal of The Geomorphological Association of Korea
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    • v.20 no.3
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    • pp.41-53
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    • 2013
  • This research was carried out to classify erosion shapes and sea-cliff erosion rates were estimated through periodic field survey in Dundu-ri, Anmyeondo. Based on the results of field measurements using the datum-point, the annual sea-cliff erosion rate was estimated about 25~102cm/yr by point. The erosion rate gradually increases from spring to summer, but tends to decrease slightly in autumn. Specifically, the erosion rate between June and July indicated a rather decreasing trend, but showed a sharp increase between July and September. This was attributed to erosion that proceeds more rapidly than during other periods due to severe rainstorms in summer that had a direct impact on the study area as well as storm surges caused by hurricanes. Afterwards, the sea-cliff erosion rate gradually decreased in autumn, but reflected an increasing trend again from December to January. This was attributed to the mechanical weathering that actively progresses as bed rocks on the sea-cliff undergo repeated freezing and thawing in winter. The seacliff in Dundu-ri is divided into three types according to the erosion shape. First, Type A is observed in the sea-cliff composed of the same bed rocks and hard rock stratum. Second, Type B is found in the sea-cliff with a relatively gentler slope compared to Type A, since weathering material including soil is formed on the surface of the sea-cliff consisting of the same bed rocks and hard rock stratum. Lastly, Type C is observed in the sea-cliff where hard rock stratum is mixed with soft rock stratum. In this case, the soft rock stratum slumps and erodes first by precipitation and wave energy, followed by additional slumping of the exposed hard rock stratum.

Characteristics Variation of the Sedimentary Environment in Winter Season around the Baramarae Beach of Anmyeondo Using Surface Sediment Analysis (표층퇴적물 분석을 통한 동계 안면도 바람아래해수욕장 주변의 퇴적환경 변화특성)

  • JANG, Dong-Ho;KIM, Jang-Soo;PARK, No-Wook
    • Journal of The Geomorphological Association of Korea
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    • v.17 no.1
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    • pp.15-27
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    • 2010
  • This study investigated the sedimentary environment changes in the Baramarae beach of Anmyeondo through spatio-temporal surface sediment analysis. In the winter season 2009, surface sediments were classified into 7 sedimentary facies such as gravel, sand, gravelly sand, gravelly muddy sand, muddy sand, silty sand, and sandy silt. Time-series analysis of average grain size from 2002 to 2009 revealed that the average grain size of sediments became finer and sorting was much worse. On the contrary, during the same period, the grain size became coarsening-trend and sorting was much better in beach area. These different grain size patterns resulted from the different change characteristics of beach and tidal flats. The southwestern beach area was connected to the open sea and thus fine sediments were removed by the environments with relatively high-energy. The sedimentation of fine sediments in the bay resulted from the tidal current action and the reduction of energy by the topographic effects. Fine sediments in the outer part of southwestern tidal flats could be explained such that the Seomot isle blocked ocean waves and as a result, low-energy environments accelerated sedimentations of fine sediments.

Time-series Analysis of Baramarae Beach in Anmyeondo Using Aerial Photographs and Field Measurement Data (항공사진과 기준목 측정자료를 이용한 안면도 바람아래 해빈의 시계열 변화 분석)

  • KIM, Jang-soo;JANG, Dong-Ho
    • Journal of The Geomorphological Association of Korea
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    • v.18 no.2
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    • pp.39-51
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    • 2011
  • In this study, the shape of the Baramarae beach, Anmyeondo Area in West Coast of Korea and the changes in the sedimentation and erosion environment were analyzed in time series. As a result of the time series analysis of the shape of the Baramarae beach using aerial photographs from 1967 to 2009, the sand spit that developed in the southern part of Halmi Island was found to have had an EEN direction, but it was changed to a NNS direction, as reflected in the 2009 aerial photographs, as it gradually shifted to the west. In the onsite measurement, the H-3, H-4, H-5, and H-6 spots showed a superior sedimentation environment and the H-7, H-8, and H-9 spots showed a superior erosion environment. It was thus found that sedimentation is superior in the southwest beach and that erosion is superior in the northeast beach. The results in the spots between H-3 and H-6 indicate that the sand in the beach could not move to the northeast beach of Halmi Island due to the bank that had been established in the southwest beach of the island. On the other hand, it seems that superior erosion takes place in spots H-7 to H-9 in the northeast beach, where sand is not provided from the southwest beach of Halmi Island. It was found from the seasonal analysis that the season when superior sedimentation takes place in all the spots is autumn, and that the season when superior erosion takes place is summer. Superior sedimentation takes place in winter and spring in the southeast side and in summer in the northwest side.

A Study on the Generation and Movement of Low-concentration $CO_2$ in Summer at Gosan, Korea (제주도 고산지역 여름철 저농도 이산화탄소의 발생원인과 이동경로에 관한 연구)

  • Kang, Kyeoung-Sik;Moon, Il-Ju;Hwang, Seung-Man;Shin, Dong-Suk;Yoon, Soon-Chang
    • Atmosphere
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    • v.20 no.3
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    • pp.307-318
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    • 2010
  • This study investigates the generation and movement of low-concentration $CO_2$ observed in Gosan during summer from 2002 to 2006. For analysis, additional $CO_2$ data in Anmyeondo, Ryori, Barrow, and Minamitorishima as well as NOAA/ESRL daily global $CO_2$ fields, background trajectories data, and 850 hPa wind fields are also used. Based on analyses using various observed data, we classified three types of low-concentration $CO_2$ in Gosan according to its origin: i) the origin of the Siberian continental, in which the consumption of $CO_2$ is active due to photosynthesis from broad forests, ii) the origin of Okhotsh and Artic seas, in which the low-concentration $CO_2$ is dominant due to high primary productivity by a plankton bloom, and iii) the origin of the Northwestern Pacific which is related to the entry of air mass from high latitudes. These results show that the low-concentration $CO_2$ observed in Gosan during summer is not originated from the Pacific oceans as known in previous studies, but originated from high latitude regions such as the Siberian continental and the Okhotsh and Artic seas.

DECORANA and TWINSPAN Aided Analysis of Koelreuteria paniculata Community Formation (DECORANA와 TWINSPAN을 이용한 모감주나무 (Koelreuteria paniculata)군락 유형 분석)

  • Kim Jong-Hyun;Park Ji-Min;Jung Kyung-Su;Ri Chong-Un
    • Korean Journal of Environment and Ecology
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    • v.19 no.1
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    • pp.9-18
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    • 2005
  • We analyzed community forming patterns and forest vegetation of goldenrain tree communities in Anmyeondo, Daegu Naegokdong, Pohang Youkangri, Yanghakri, Balsanri, Daedongbaeri, Mophori and Seochonri. The vegetation data for analysis collected from 68 quadrats of 8 sites Using the Braun-Blanquet method, from April 2002 to September 2003. A total of 201 species were found and the area was covered with $30\~100\%$ of tree layer, $0\~90\%$ of shrub layer and $20\~100\%$ of herb layer. Oplismenus undulatifolius, Pueraria thunbergiana, Quercus dentata, Clematis apiifolia, Ligustrum obtusifolium, Rosa multiflora, Artemisia princeps var. orientalis, Humulus japonicus and Robinia pseudo -acacia were the species in high frequency. To analyze the community classification and ordination, we used the technique of TWINSPAN and DECORANA. The surveyed areas with 68 quadrats were divided into 3 groups by TWINSPAN and divided into 3 communities with axis 1 date volume by DECORANA.