• Title/Summary/Keyword: Northern Korean peninsula

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A Study on the Residual Current in the Cheju Strait (제주해협의 해수유동특성에 관한 연구)

  • KIM Sang Hyun;RHO Hong Kil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.5
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    • pp.759-770
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    • 1997
  • The general flow patterns in the Cheju Strait have been investicated by analyzing the current observations measured in $1986\~1989$ by current meter mooring in 3 north-south sections in the Cheju Strait and at 4 observation points around Cheju Harbour, and measured in $1981\~1987$ by drogue tracking. 1. In the Cheju Strait, there are eastward or northeastward residual currents, which implies that sea waters flow into through the whole western section and flow out through the whole eastern section in the Cheju Strait. The velocity of residual currents are $5.2\~30\;cm/sec$ in 10 m layer and $1.3\~24cm/sec$ in mid-bottom layer. Generally, the flow is strong along the deepest through and the northern part, and weak in the shallow areas near Chuja Islands and Bogil Island. 2. In the western entrance of the Cheju Strait, the observed mean residual velocity is 6.93 cm/sec and the volume transport is 0.384 Sv. There are a big discrepancy between the observed residual currents and the geostrophic currents. 3. Near the frontal areas northwest to Chuja Islands, warm and saline offshore waters, flow northward about 5 miles into the southern coastal areas of the Korean Peninsula in flood, and flow back rather eastward or southeastward than southward in ebb. So, warm and saline waters flow along coastal areas, being mixed with coastal waters. As a result, the northwestern area of Chuja Islands plays a role of the entrance of influx of warm and saline offshore water to the southwestern coastal areas of the Korean Peninsula. It should be stressed that this flow pattern is not due to the residual flows, but to the temporal (tidal) flows.

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Floristic Study of County Pyeong-chang and Yeong-wol including Limestone Regions (Prov. Gangwon-do) from Korea (평창, 영월(강원도)의 석회암 지역 식물상)

  • Nam, Gi-Heum;Kim, Jung-Hyun;Kim, Young-Chul;Kim, Jin-Seok;Lee, Byoung-Yoon
    • Korean Journal of Environment and Ecology
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    • v.26 no.1
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    • pp.11-38
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    • 2012
  • Located in the middle part of the Korean peninsula, Pyeong-chang and Yeong-wol (Gangwon-do) areas are limestone regions that are important biogeographically showing the peculiar flora. In order to manage efficiently endangered and rare plant species, we have investigated flora of these above regions from March to October, 2010. The result of the investigation showed a total of vascular plants of 1,145 taxa; 134 families, 503 genera, and 1,010 species, 11 subspecies, 110 varieties, 10 forms and four hybrids. Among taxa investigated, endangered species designated by the law called 'Protection Law for Endangered wild fauna and flora' were seven taxa, and 50 taxa were considered to be endemic to Korea. Based on the floristic degrees categorized by the specific distribution of plant species, 24 taxa revealed the floristic degree (FD) V, 30 for FD IV, and 60 for FD III, 45 for FD II and 79 taxa for FD I. The 82 taxa were identified to be naturalized. Of those species investigated in this survey, 53 taxa were identified as specific ones biogeographically as compared to flora of other terrestrial regions; 35 of calcicolous plants, 15 with distribution in the northern part of the Korean peninsula, three with coastal habitats.

Potential Impact of Climate Change on Distribution of Warm Temperate Evergreen Broad-leaved Trees in the Korean Peninsula (기후변화에 따른 한반도 난대성 상록활엽수 잠재서식지 분포 변화)

  • Park, Seon Uk;Koo, Kyung Ah;Kong, Woo-Seok
    • Journal of the Korean Geographical Society
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    • v.51 no.2
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    • pp.201-217
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    • 2016
  • We accessed the climate change effects on the distributions of warm-evergreen broad-leaved trees (shorten to warm-evergreens below) in the Korean Peninsula (KP). For this, we first selected nine warm-evergreens with the northern distribution limits at mid-coastal areas of KP and climate variables, coldest month mean temperature and coldest quarter precipitation, known to be important for warm-evergreens growth and survival. Next, species distribution models (SDMs) were constructed with generalized additive model (GAM) algorithm for each warm-evergreen. SDMs projected the potential geographical distributions of warm evergreens under current and future climate conditions in associations with land uses. The nine species were categorized into three groups (mid-coastal, southwest-coastal, and southeast-inland) based on their current spatial patterns. The effects of climate change and land uses on the distributions depend on the current spatial patterns. As considering land uses, the potential current habitats of all warm-evergreens decrease over 60%, showing the highest reduction rate for the Kyungsang-inland group. SDMs forecasted the expansion of potential habitats for all warm-evergreens under climate changes projected for 2050 and 2070. However, the expansion patterns were different among three groups. The spatial patterns of projected coldest quarter precipitation in 2050 and 2070 could account for such differences.

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Characteristics of Meteorological Variables in the Leeward Side associated with the Downslope Windstorm over the Yeongdong Region (영동지역 지형성 강풍과 관련된 풍하측 기상요소의 특징)

  • Cho, Young-Jun;Kwon, Tae-Yong;Choi, Byoung-Cheol
    • Journal of the Korean earth science society
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    • v.36 no.4
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    • pp.315-329
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    • 2015
  • We investigated the characteristics of meteorological conditions related to the strong downslope wind over the leeward side of the Taebaek Mountains during the period 2005~2010. The days showing the strong wind exceeding $14ms^{-1}$ in Gangwon province were selected as study cases. A total of 15 days of strong wind were observed at Sokcho, Gangneung, Donghae, and Taebaek located over the Yeongdong region. Seven cases related to tropical cyclone (3 cases) and heavy snowfall (2 cases) and heavy rainfall (2 cases) over the Yeongdong region were excluded. To investigate the characteristics of the remaining 8 cases, we used synoptic weather chart, Sokcho radiosonde, Gangneung wind profiler and numerical model. The cases showed no precipitation (or ${\leq}1mm\;day^{-1}$). From the surface and upper level weather chart, we found the pressure distribution of southern high and northern low pattern over the Korean peninsula and warm ridge over the Yeongdong region. Inversion layer (or stable layer) and warm ridge with strong wind were located in about 1~3 km (925~700 hPa) over mountains. The Regional Data Assimilation and Prediction System (RDAPS) indicated that warm core and temperature ridge with horizontal temperature gradient were $0.10{\sim}0.23^{\circ}C\;km^{-1}$ which were located on 850 hPa pressure level above mountaintop. These results were summarized as a forecasting guidance of downslope windstorm in the Yeongdong region.

Vascular Plants Distributed in Ridge of the Northernmost Baekdudaegan Mountains(Hyangrobong~Guryongryeong) (최북단 백두대간(향로봉~구룡령) 능선부에 분포하는 관속식물상)

  • Oh, Hyunkyung;You, Juhan
    • Journal of Environmental Impact Assessment
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    • v.28 no.4
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    • pp.347-372
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    • 2019
  • The purpose of this study is to provide the basic data for management of the ecosystem of Baekdudaegan Mountains by surveying and analysing the vascular plants distributed from Hyangrobong area to Guryongryeong area. The numbers of vascular plants in the whole survey areas were summarized as 633 taxa including 95 families, 321 genera, 549 species, 4 subspecies, 70 varieties, and 10 forms. There were 285 taxa in Hyangrobong area, 256 taxa in Masanbong area, 318 taxa in Mt. Seoraksan area, 281 taxa in Mt. Jeombongsan area, 173 taxa in Bukamryeong and Ohsaekcheon valley area, 197 taxa in Soenadeuri area, 203 taxa in Yeongarigol area, and 168 taxa in Guryongryeong area. The endangered species were 2 taxa including Leontice microrrhyncha and Smilacina bicolor. The rare plants were 39 taxa including Pinus pumila, Halenia corniculata, Juniperus chinensis var. sargentii, and so forth. In IUCN Red List categories, there were 2 taxa of CR, 7 taxa of EN, 10 taxa of VU, 18 taxa of LC, and 2 taxa of DD. The Korean endemic plants were 23 taxa including Salix koriyanagi, Anemone koraiensis, Lespedeza maritima, Cirsium setidens, Saussurea seoulensis, Carex okamotoi, and so forth. The plants adaptable to climate change were 48 taxa including 17 taxa of endemic plants, 1 taxon of southern plant, and 30 taxa of northern plants. The naturalized plants were 32 taxa including Fallopia dumetorum, Cerastium glomeratum, Papaverrhoeas, Bidensfrondosa, Lolium perenne, and so forth. The invasive alien plants were 3 taxa including Rumex acetocella, Ambrosia artemisiifolia, and Ambrosia trifida.

Evaluation of Low-temperature Compaction Characteristics According to Organic Matter Content through Laboratory Compaction Tests (실내 다짐시험을 통한 유기물 함량에 따른 저온 다짐 특성 분석)

  • Choi, Hyun-Jun;Kim, Sewon;Lee, Seungjoo;Park, Hyeontae;Choi, Hangseok;Kim, YoungSeok
    • Journal of the Korean Geotechnical Society
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    • v.40 no.3
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    • pp.93-100
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    • 2024
  • Pore water freezes in low-temperature compaction, which leads to different compaction characteristics compared to room temperature conditions. In regions like Alberta, Canada, where organic soils are prevalent, compaction performance is influenced by the high water retention and compressibility of organic soils, as well as their sensitivity to freezing and thawing. Alberta's strict environmental regulations demand the reuse of excavated soil for backfill, and the long winter season creates challenging conditions for civil engineering projects. In this study, a laboratory compaction test was conducted to evaluate the low-temperature compaction characteristics of organic soils with varying organic content. The results indicate that the optimum moisture content increases as the organic content increases, and the maximum dry unit weight decreases by up to 21.9%. In addition, under temperature conditions below -4℃, no optimum moisture content was observed, and the dry unit weight decreased as the moisture content increased.

A GIS-based Analysis on Geometric Distortions in Historical Maps: A Preliminary Case Study of Daedongyeojido ('The Great Map of Korea') (고지도의 왜곡 양상에 대한 GIS-기반 연구: 대동여지도를 사례로 한 시론적 분석)

  • Lee, Sang-Il;Cho, Daeheon
    • Journal of the Korean Geographical Society
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    • v.49 no.3
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    • pp.438-455
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    • 2014
  • This study aims at providing a set of viable answers regarding the projection and cartographic scale of Daedongyeojido through a GIS-based planimetric accuracy analysis. Both global and local analyses were undertaken in the use of an analytical tool, MapAnalyst. The main results from the global analysis are threefold. First, the overall cartographic scale turned out to be between 1:158,000 and 1:162,000. Second, the rotation angles were between $2^{\circ}$ and $3^{\circ}$, and the equidistant cylindrical projection reported the smallest value. Third, in terms of position accuracy, the conformal cylindrical projection showed a best fit to the map. A local analysis was undertaken for the conformal cylindrical and equidistant azimuthal projections and its main results are threefold. First, the largest distortions in terms of the displacement vectors and distortion grid were found in the northern borderlands. Second, from the isoline maps of scales, it was acknowledged that local scales between 1:170,000 and 1:175,000 were found around the middle part of the Korean peninsula centered on Seoul. As away from the region to the north-south direction, increasingly larger scales were distributed, while the smallest ones were found in the western and eastern edges of the peninsula. Third, from the isoline maps of rotation, it was known that areas west of a northernmost city (Junggangjin) were substantially rotated to the west, while ones east of it to the east. For a more sophisticated analysis, some need to be done to have a larger set of control points, a better way of postulating the map projection, and a more advanced set of techniques for a local analysis.

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Synoptic Climatological Characteristics of Distribution of Precipitation in Korea in Early Autumn (한국의 초가을 강수분포의 종관기후학적 특성)

  • Yang, Jin-Suk
    • Journal of the Korean association of regional geographers
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    • v.5 no.1
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    • pp.151-162
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    • 1999
  • This study is a comparative analysis of sea level and 500hPa surfaces between dry year and wet year, which are selected by variability of precipitation and standardized anomalies in Korea in early autumn. While the amount of precipitation of early autumn decreases, the variability of precipitation increases rapidly reflecting the strength and weakness of Kaul Changma front and the occurrences of the typhoonic precipitation. The regional distribution of the variability of precipitation shows west-high, east-low pattern in which the east coast and the southeastern coast shows low, but high in the southwestern coast. In the anomalies distribution of sea-level and 500hPa surfaces, during dry year, the northern part of Siberia and the core area of North Pacific high shows negative anomalies, on the contrary, there were positive anomalies in wet year at the same areas. In addition, at the 500hPa level, while the Korean peninsula was located at the west of deep trough with low zonal index in dry year, the peninsula was influenced by weak trough with high zonal index showing strong zonal flow in wet year. During dry year the height of 500hPa surface is low at the north of $40^{\circ}N$, but high in wet year. In consequences, this study identified that the occurrences of dry year and wet year were influenced by the seasonal variations of the strength and the weakness of North Pacific high and Siberian high.

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A Study on the Forest Survey Project(1910) (임적조사사업(林籍調査事業)(1910)에 관한 연구(硏究))

  • Bae, Jae Soo
    • Journal of Korean Society of Forest Science
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    • v.89 no.2
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    • pp.260-274
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    • 2000
  • The purposes of this study were to reveal the backgrounds, process, and evaluation of the "Forest Survey Project(1910)" and to determine the influence of the "Comments on the Classification of Forest Land Ownership in Korea(1910)", which was based upon the results of the project, on forest policy in the early period of the General-Government of Korea. The forest survey project was conducted by two Japanese, Kiuchi and Saito, to understand the forest distribution in the Korean Peninsula by ownership and stand. However, the accuracy of the project was very low due to the lack of budget and time. Especially, village forests and special easement forests in the northern peninsula were classified into the Nation Forest without Administration caused by the informality and arbitrariness of the survey. Nevertheless, the General-Government of Korea used the results of the survey for establishing the forest policy on the classification of the forest land ownership in Korea at that time. The "Comments on the Classification of Forest Land Ownership in Korea(1910)" was based upon the results of the survey as mentioned above. The comments was realized as colonial forest policy through the Forest Ordinance in 1911 and a series of policies consolidating the modern forest ownership. To conclude, the "Forest Survey Project" was used to establish colonial forest policy in the early of the General-Government of Korea while its accuracy was truly low. Moreover, the "Comments on the Classification of Forest Land Ownership in Korea" had a great influence on the formulating the directions and details of colonial forest policy in Korea under the rule of Japanese Imperialism.

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The Growth and Locality of Mahan(馬韓) Seen through the Pottery in Tombs (분묘 출토 토기로 살펴본 마한의 성장과 지역성)

  • Kim, Nak Jung
    • Korean Journal of Heritage: History & Science
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    • v.49 no.4
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    • pp.126-155
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    • 2016
  • This article deals with some issues with respect to the Mahan pottery excavated from the tombs. Pedestal jars with cover, small round-bottom jars, cylindrical pottery etc. had appeared in the interaction with the northern region in the dimension of the southern Korean peninsula. Especially, these relics had an important role at the route connecting the midwest region, Chungcheong(忠淸) inland and Yeongnam(嶺南) region. By this stage, the iron culture was similar to each other in the southern Korean peninsula. In addition to the inland route, the coastal passage along the west coast seems to have been used. Such signs are found in cylindrical pottery and Pedestal jars with cover. It was probably a natural phenomenon that the most powerful forces of Mahan appeared at this crossroad of cultural exchange. The unique style of Mahan pottery such as double-rim pottery had been established since the third century. After the third century, Mahan pottery varied by region depending on the tomb style. The difference roughly matches with the variations of the tomb style. But at the region of Bungumyo(mounded tomb), specific pottery such double-rim pottery had been prevalent than in other regions. And a specific style had been used in a narrow range. The pottery spread to the neighboring regions in the course of interaction and were also used in ritual practices.