• Title/Summary/Keyword: slope morphology

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Impact Assessment of Sea_Level Rise based on Coastal Vulnerability Index (연안 취약성 지수를 활용한 해수면 상승 영향평가 방안 연구)

  • Lee, Haemi;Kang, Tae soon;Cho, Kwangwoo
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.27 no.5
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    • pp.304-314
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    • 2015
  • We have reviewed the current status of coastal vulnerability index(CVI) to be guided into an appropriate CVI development for Korean coast and applied a methodology into the east coast of Korea to quantify coastal vulnerability by future sea_level rise. The CVIs reviewed includes USGS CVI, sea_level rise CVI, compound CVI, and multi scale CVI. The USGS CVI, expressed into the external forcing of sea_level rise, wave and tide, and adaptive capacity of morphology, erosion and slope, is adopted here for CVI quantification. The range of CVI is 1.826~22.361 with a mean of 7.085 for present condition and increases into 2.887~30.619 with a mean of 12.361 for the year of 2100(1 m sea_level rise). The index "VERY HIGH" is currently 8.57% of the coast and occupies 35.56% in 2100. The pattern of CVI change by sea_level rise is different to different local areas, and Gangneung, Yangyang and Goseong show the highest increase. The land use pattern in the "VERY HIGH" index is dominated by both human system of housing complex, road, cropland, etc, and natural system of sand, wetland, forestry, etc., which suggests existing land utilization should be reframed in the era of climate change. Though CVI approach is highly efficient to deal with a large set of climate scenarios entailed in climate impact assessment due to uncertainties, we also propose three_level assessment for the application of CVI methodology in the site specific adaptation such as first screening assessment by CVI, second scoping assessment by impact model, and final risk quantification with the result of impact model.

Seedling Growth and Morphology as Influenced by Removal of Cotyledon and Unifoliolate in White Clover (자엽 및 단엽 제거에 따른 White Clover의 유묘기 생장과 형태적 특성)

  • 강진호;박진서;이희원
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.39 no.5
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    • pp.480-488
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    • 1994
  • Low seedling growth rates of white clover (Trifolium repens L.) have been limited its good establishment to pastures. The experiment was done to determine the effect of removal of cotyledon and unifoliolate on the growth and morphological characters of contrasting white clover cultivars for 8 weeks after the treatment. Individual plants of cv. Regal (large leaf), Louisiana S-l (medium-large leaf), Grasslands Huia (medium-small leaf) and Aberystwyth S184 (small leaf) were grown in 10cm plastic pot containing a 2:1:1 soil:sand:peat moss mixture until the cotyledon or unifoliolate stage and then removed one (C1) or two cotyledons (C2) at cotyledon stage, and unifoliolate only (U), unifoliolate and one cotyledon (DC1) or unifoliolate and two cotyledons (DC2) at the unifoliolate stage. To measure the removal effect on biomass and morphological characters (leaf area, petiole and stolon lengths, growing tips and leaves), plants were sampled 4, 6 and 8 weeks after the treatment. Intact plants had greater biomass and morphological characters than removal-treated ones, Removal treatments at cotyledon stage, C1 and C2, were decreased more biomass and morphological characters than removal ones at unifoliolate stage while the severer cotyledon removal, the more reduction. Stolon length per plant and petiole length markedly inclined 6 weeks after the treatments although biomass and the other characters continuously did. Relatively large-leaved cultivar had more biomass, leaf area per plant and longer petiole than the other(s) but the reverse results were true in stolon length, growing tips and no. of leaves per plant. Biomass was linearly increased with increased leaf area but the earlier and severer removal, the less slope. The severer damage of cotyledon and unifoliolate had detrimental effects on the growth and aftermath establishment of white clover

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A Study on Characteristic of Forest Vegetation and Site in Mt. Odae(I) -Classification of Plant Community in Tongdaesan- (오대산(五臺山)의 산림식생(山林植生)과 입지특성(立地特性)에 관한 연구(硏究)(I) - 동대산지역(東臺山地域)의 식물군락분류(植物群落分類) -)

  • Lee, Sun
    • Journal of Korean Society of Forest Science
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    • v.89 no.2
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    • pp.173-184
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    • 2000
  • The aim of this study was to characterize the forest vegetation and site of Tongdaesan(Odaesan National Park) for ecological forest management. The deciduous forests of Tongdaesan are the result of cool, temperate climate. Direction and slope morphology contribute to differences in species composition and vegetaion structure. Based on the BRAUN-BLANQUET-approach, 242 releves were recorded and subsequently classified. The vegetation could be divided into two forest community groups, seven forest communities, and several groups. South exposed, dry slopes were covered with forests of the Quercus mongolica-Acer pseudo-sieboldianum community group. Differential species included grasses and sedges, e.g., Calamagrostis langsdorfii, Carex humilis and C. lanceolata. Quercus mongolica-Acer pseudo-sieboldianum community group could be subdivided into Rhododendron mucronulatum var. ciliatum community, Lespedeza${\times}$tomentella community, Carex humilis-Maackia amurensis community, Quercus mongolica-Acer pseudosieboldianum typical community and Pimpinella brachycarpa community. Carex humilis-Maackia amurensis community was divided into Galium kinuta subcommunity and typical subcommunity. Pimpinella brachycarpa community was divided into Vicia venosa var. cuspidata subcommunity and typical subcommunity. On north exposed, more humid and moist sites, forests of the Dryopteris crassirhizoma-Cornus controversa community group were found. This group was subdivided into Acer tschonoskii var. rubripes-Acer tegmentosum community and Deutzia glabrata-Ulmus laciniata community. Deutzia glabrata-Ulmus laciniata community was divided into Acer tegmentosum subcommunity, Saxifraga punctata subcommunity and typical subcommunity.

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A Study on the Boulder Stream of Granitoid in Korea (한국 화강암질암류 산지에서 발달하는 암괴류에 관한 연구)

  • Jeon, Young-Gweon
    • Journal of the Korean association of regional geographers
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    • v.6 no.2
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    • pp.71-82
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    • 2000
  • The purpose of this paper is to clarify geomorphic features and development on the boulder stream of granitoid in Korea. Considering the purpose and the method of this paper, three boulder streams are selected : Biseulsan(Mt. Biseul) boulder stream (Daegu city), Maneosan (Mt. Maneo) boulder stream(Gyeongnam province), Geumjeongsan(Mt. Geumjeong) boulder stream (Busan city). The boulder streams mentioned above are bigger in scale and more typical in shape than any other ones in the Korean Peninsula. The main results are summarized as follows. 1. The following are the main features of the boulder streams morphology : the mean gradient is $3{\sim}25^{\circ}$, the longer axes of the component boulders within the deposits averaged about 2m in length, the shapes of the component boulders may be both subangular and subrounded features. 2. The formation of the component boulders is associated with deep weathering of granitoid under warm humid conditions, and the downward movement of boulders occurred by solifluction and frost creep under periglacial conditions. 3. The geomorphic development stage of the boulder streams may be classified into four stages. These boulder streams come under fossil landform stage, the 4th stage ; evidence provided by lichens and weathering features indicate inactive or fossil landform. 4. In generally, boulder streams are well developed on shallow valley floors.

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Tectonic Structures and Hydrocarbon Potential in the Central Bransfield Basin, Antarctica (남극 브랜스필드 해협 중앙분지의 지체구조 및 석유부존 가능성)

  • Huh Sik;Kim Yeadong;Cheong Dae-Kyo;Jin Young Keun;Nam Sang Heon
    • The Korean Journal of Petroleum Geology
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    • v.5 no.1_2 s.6
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    • pp.9-15
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    • 1997
  • The study area is located in the Central Bransfield Basin, Antarctica. To analyze the morphology of seafloor, structure of basement, and seismic stratigraphy of the sedimentary layers, we have acquired, processed, and interpreted the multi-channel seismic data. The northwest-southeastern back-arc extension dramatically changes seafloor morphology, volcanic and fault distribution, and basin structure along the spreading ridges. The northern continental shelf shows a narrow, steep topography. In contrast, the continental shelf or slope in the south, which is connected to the Antarctic Peninsula, has a gentle gradient. Volcanic activities resulted in the formation of large volcanos and basement highs near the spreading center, and small-scale volcanic diapirs on the shelf. A very long, continuous normal fault characterizes the northern shelf, whereas several basinward synthetic faults probably detach into the master fault in the south. Four transfer faults, the northwest-southeastern deep-parallel structures, controlled the complex distributions of the volcanos, normal faults, depocenters, and possibly hydrocarbon provinces in the study area. They have also deformed the basement structure and depositional pattern. Even though the Bransfield Basin was believed to be formed in the Late Cenozoic (about 4 Ma), the hydrocarbon potential may be very high due to thick sediment accumulation, high organic contents, high heat flow resulted from the active tectonics, and adequate traps.

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Variations in Morphological and Geochemical Characteristics in Manganese Nodules from the East Siberian Arctic Shelf with Varying Water Depths (동시베리아해 대륙붕에서 산출되는 망가니즈단괴의 수심에 따른 형태학적·지화학적 특성 변화)

  • Hyo-Jin Koo;Hyen-Goo Cho;Sangmi Lee;Gi-Teak Lim;Hyo-Im Kim
    • Economic and Environmental Geology
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    • v.56 no.1
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    • pp.1-11
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    • 2023
  • In this study, we explore the morphological and geochemical characteristics for 440 manganese nodules collected from two different water depths [ARA12B-St52 (150 m, n = 239) and ARA12B-St58i (73 m, n = 201)] on the continental shelf of the East Siberian Sea from the ARA12B expedition in 2021. We also discussed the variations in the characteristics of manganese nodules with varying water depths in the Arctic Sea. The sizes of the nodules are generally greater than 3 cm at both sites. However, there is an obvious difference in the morphology with water depths. For the nodules collected at 150 m, brown-black colored tabular, tube, and ellipsoidal shapes with a rough surface texture are dominant. On the other hand, yellow-brown tabular shapes with a smooth surface texture are common for the nodules collected at 73 m. Furthermore, the slope of trend line between size and weight is significantly different at both sites: particularly, the slopes of nodules at 150 and 73 m are 1.60 and 0.84, respectively. This indicates the difference in the internal structure, porosity, and constituting elements between both nodules. Micro X-ray Flourescence (µ-XRF) results clearly demonstrate that the internal textures and chemical compositions are different with water depths. The nodules at 150 m are composed of a thick Mn-layer and a thin Fe-layer centered on the nucleus, while the nodules at 73 m are alternately grown with thin Mn- and Fe- layers around the nucleus. The average chemical compositions obtained by µ-XRF are 40.6 wt% Mn, 5.2 wt% Fe, and 7.9 Mn/Fe ratio at 150 m, and 10.3 wt% Mn, 19.0 wt% Fe, and 0.6 Mn/Fe ratio at 73 m. The chemical compositions of the nodules at 150 m are similar to those of nodules from the Peru Basin in the Pacific Ocean, while the compositions of the nodules at 73 m are similar to those of nodules from the Cook Islands or the Baltic Sea. The observed morphological and geochemical characteristics of the nodules show a clear difference at the two sites, which indicates that the aqueous conditions and formation processes of the nodules in the Arctic Sea vary with the water depths.

한강하류지형면의 분류와 지형발달에 대한 연구 (양수리에서 능곡까지)

  • Park, No-Sik
    • Journal of the Speleological Society of Korea
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    • no.68
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    • pp.23-73
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    • 2005
  • Purpose of study; The purpose of this study is specifically classified as two parts. The one is to attempt the chronological annals of Quaternary topographic surface through the study over the formation process of alluvial surfaces in our country, setting forth the alluvial surfaces lower-parts of Han River area, as the basic deposit, and comparing it to the marginal landform surfaces. The other is to attempt the classification of micro morphology based on the and condition premising the land use as a link for the regional development in the lower-parts of Han river area. Reasons why selected the Lower-parts of Han river area as study objects: 1. The change of river course in this area is very serve both in vertical and horizontal sides. With a situation it is very easy to know about the old geography related to the formation process of topography. 2. The component materials of gravel, sand, silt and clay are deposited in this area. Making it the available data, it is possible to consider about not oかy the formation process of topography but alsoon the development history to some extent. 3. The earthen vessel, a fossil shell fish, bone, cnarcoal and sea-weed are included in the alluvial deposition in this area. These can be also valuable data related to the chronological annals. 4. The bottom set conglometate beds is also included in the alluvial deposits. This can be also valuable data related to the research of geomorphological development. 5. Around of this area the medium landform surface, lower landform surface, pediment and basin, are existed, and these enable the comparison between the erosion surfaces and the alluvial surfaces. Approach : 1. Referring to the change of river beds, I have calculated the vertical and horizontal differences comparing the topographic map published in 1916 with that published in 1966 and through the field work 2. In classifying the landform, I have applied the method of micro morphological classification in accordance with the synthetic index based upon the land conditions, and furthermore used the classification method comparing the topographic map published in 1916 and in that of 1966. 3. I have accorded this classification with the classification by mapping through appliying the method of classification in the development history for the field work making the component materials as the available data. 4. I have used the component materials, which were picked up form the outcrop of 10 places and bored at 5 places, as the available data. 5. I have referred to Hydrological survey data of the ministry of Construction (since 1916) on the overflow of Han-river, and used geologic map of Seoul metropolitan area. Survey Data, and general map published in 1916 by the Japanese Army Survbey Dept., and map published in 1966 by the Construction Research Laboratory and ROK Army Survey Dept., respectively. Conclusion: 1. Classification of Morphology: I have added the historical consideration for development, making the component materials and fossil as the data, to the typical consideration in accordance with the map of summit level, reliefe and slope distribution. In connection with the erosion surface, I have divided into three classification such as high, medium and low-,level landform surfaces which were classified as high and low level landform surfaces in past. furthermore I have divided the low level landform surface two parts, namely upper-parts(200-300m) and bellow-parts(${\pm}100m$). Accordingly, we can recognize the three-parts of erosion surface including the medium level landform surface (500-600m) in this area. (see table 22). In condition with the alluvial surfaces I have classified as two landform surfaces (old and new) which was regarded as one face in past. Meamwhile, under the premise of land use, the synthetic, micro morphological classification based upon the land condition is as per the draw No. 19-1. This is the quite new method of classification which was at first attempted in this country. 2. I have learned that the change of river was most severe at seeing the river meandering rate from Dangjung-ni to Nanjido. As you seee the table and the vertical and horizontal change of river beds is justly proportionable to the river meandering rate. 3. It can be learned at seeing the analysis of component materials of alluvial deposits that the component from each other by areas, however, in the deposits relationship upper stream, and between upper parts and below parts I couldn't always find out the regular ones. 4. Having earthern vessel, shell bone, fossil charcoal and and seaweeds includen in the component materials such as gravel, clay, sand and silt in Dukso and Songpa deposits area. I have become to attempt the compilation of chronicle as yon see in the table 22. 5. In according to hearing of basemen excavation, the bottom set conglomerate beds of Dukso beds of Dukso-beds is 7m and Songpa-beds is 10m. In according to information of dredger it is approx. 20m in the down stream. 6. Making these two beds as the standard beds, I have compared it to other beds. 7 The coarse sand beds which is covering the clay-beds of Dukso-beds and Nanjidobeds is shown the existence of so-called erosion period which formed the gap among the alluvial deposits of stratum. The former has been proved by the sorting, bedding and roundness which was supplied by the main stream and later by the branch stream, respectively. 8. If the clay-beds of Dukeo-bed and Songpa-bed is called as being transgressive overlap, by the Eustatic movement after glacial age, the bottom set conglomerate beds shall be called as being regressive overlap at the holocene. This has the closest relationship with the basin formation movement of Seoul besides the Eustatic movement. 9. The silt-beds which is the main component of deposits of flood plain, is regarded as being deposited at the Holocene in the comb ceramic and plain pottery ages. This has the closest relationship with the change of river course and river beds.

Correlations between the Stream Morphological Characteristics and the Hydraulic Geometry Characteristics for the Basin (유역(流域)의 하천형태학적(河川形態學的) 특성(特性)과 수리기하학적(水理幾何學的) 특성(特性)과의 상관성(相關性))

  • Ahn, Sang Jin;Yoon, Yong Nam;Kang, Kwan Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.2 no.1
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    • pp.1-17
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    • 1982
  • The stream morphological characteristics of a river basin has a close correlation with the hydrological and hydraulic characteristics of the basin. In this study the correlations of flow duration and Hydraulic geometry with the stream morphological characteristics as well as the correlation between flow duration and hydraulic geometry were analyzed bases on the data for the Geum River basin. The purpose of this study was to provide the necessary informations for water utilization projects at ungauged locations along the river course. First of all, the stream morphological characteristics was analyzed based on the Horton's three laws on the morphology of a stream that is, the law of stream number, the law of average stream length and the law of average stream slope. As is the case for majority of the rivers it was found that the Geum River basin was well developed according to the Horton's laws. High correlations were also found between the basin characteristics and the channel characteristics. The flow duration curves obtained with the daily stream flow data of 10~90% frequency of occurences at the five stage gauging stations in the Geum River could, in general, be expressed as an exponential functional relationship. The concept of proportional stream ordering system was employed to describe continuously the longitudinal variation of the stream morphological characteristics, and the mathematical model was formulated for the discharge-frequency-proportional stream order relationship. With the morphological characteristics as a common parameter the relationships with flow duration, drainage area were established in mathematical expressions, respectively.

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