• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.370-377
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• 2018

Currently, Korea is ahead of the forest sector such as forest management, forest investigation and forest management, which is not insufficient compared with the forest advanced countries (Germany, Japan, Austria). However, there is a lack of systematic and advanced forest management plan and related research, and it is not enough to construct GIS for practical and complex analysis. Therefore, in order to perform forest analysis effectively, this study maps forest basic statistics (2010, 2015) based on GIS to map forest information. As a result, the forest area, growing stock, average growing stock, and forest rate could be produced with the maximized visual effect by detailed administrative districts, and systematic analysis of the time series changes was also possible. Forest area increased only in Goseong, Sejong, Cheolwon, Yeoncheon, Daejeon, and Seoul Guro-gu, and decreased in all other areas, while growing stock increased in most areas, Uljin, Ulleung, Seoul Nowon-gu, and Seoul Gangdong-gu. The average growing stock was found to increase in most areas excluding the four administrative districts and the forest rate was higher in 10 regions (Goseong, Yeoncheon, Gongju, Busan Dong-gu, Daegu Seo-gu, etc.) but it decreased in most regions excluding 10 regions. Based on this research, we plan to produce and analyze forest information maps for smaller administrative districts and more.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.347-353
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• 2017

In this study, numerical experiments were conducted to identify distribution of rising flow and flux in the East Sea of Korea, where the coastal upwelling occurs. Temperature and salinity data from CTD observations and NIFS during summer 2013 were applied to the model. Numerical experiments were carried out with different wind speed (3, 6 m/s and 9 m/s) and direction (southerly and southwesterly), which represent the most frequent in summer conditions. As a result of calculation, upwelling flow rate was found to be highest in Pohang between five coasts(Hupo, Youngduk, Pohang, Ulsan and Busan). Comparing with southerly wind conditions, the rising flow rate is about 1.5 times greater when southwesterly wind was applied. Horizontal diffusion of the upwelling area is expected to have a speed of 17~22 km/day when a 9 m/s southwesterly wind is applied. If this wind continues over one week, a cold pool will be generated by upwelling that may reach to the Ulleung area.

• Journal of the Korean association of regional geographers
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• v.11 no.1
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• pp.19-28
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• 2005

Although Dokdo, small and dependent islands of Ulleung County, can be considered critical in terms of both geo-politics and physical geography, it is clear that Korean geographers have been too silent tn study Dokdo. In the author's view, such tendency is partly due to difficulties in access to Dokdo. In this sense this study would be meaningful for inquiring into the regional geomorphology of Dokdo regardless of only three-day field work. The major findings of the study are as follows. Firstly, the geology of Dokdo is composed of 8 rock units. Secondly, in a slope analysis of Dokdo volcano using GIS tool, steep slopes over $26^{\circ}$ account for 79.1% of whole slopes and even free faces, defined as slopes over $40^{\circ}$, account for 65.4%. Thirdly, the main landforms of Dokdo constitute volcanic landform, coastal landform and the others, such as talus, dyke, tafoni and erosional hollow. Fourthly, it turns out that advanced landform classification map of Dokdo can be designed by taking an approach tn regional geomorphology. Finally, based on a detailed review of the latest geological literature, I argue that part of landforms of East Dokdo(dongdo) is closer tn an erosional hollow than a small crater.

• Korean Journal of Plant Taxonomy
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• v.42 no.1
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• pp.40-49
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• 2012

The NE Asiatic Solidago virgaurea complex in Korea has been reported on 5 taxa (S. virgaurea subsp. asiatica, S. virgaurea var. taquetii, S. virgaurea var. coreana, S. virgaurea subsp. leiocarpa, and S. virgaurea subsp. gigantea). However, the broad morphological variations and a lack of diagnostic characteristics have made it difficult to distinguish these taxa and have thus resulted in a complicated taxonomy in the complex. Therefore, to clarify the classification and delimitation of each taxon, the morphological characteristics of the S. virgaurea complex were investigated by examining the original descriptions and type specimens. Field work was also conducted to investigate the morphological and geographic features. In conclusion, S. japonica Kitam., as a legitimate name, was distributed all over the country except for the Is. Ulleung-do in Korea, as distinguished from S. virgaurea L. Both S. virgaurea var. taquetii and S. virgaurea var. coreana were considered as synonyms of S. japonica, as their morphological characteristics were within the variation range of those of S. japonica. Furthermore, S. virgaurea subsp. leiocarpa does not occur in Korea. Additional investigations are required to clarify the classification of S. virgaurea subsp. gigantea, whose populations were not found during the investigation in this study. S. dahurica, meanwhile, was distributed in the northern part of North Korea.

• Geophysics and Geophysical Exploration
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• v.20 no.1
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• pp.12-17
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• 2017

We construct 3D SV-wave velocity structure of the crust and the upper mantle beneath East Asia from Rayleighwave group-velocity measurements. For the construction of the SV-wave velocity model at 10 ~ 100 km depth, we used seismic data recorded at 321 broadband stations in Korea, Japan, and China. Rayleigh-wave group-velocity dispersion curves were obtained by using the multiple filtering technique in the period range from 3 to 150 s. High SV-velocity anomalies are imaged beneath the East Sea from 10 km depth to deeper depth, implying that the Moho beneath the East Sea is between at 10 ~ 20 km depth. We estimated the Moho beneath the Korean peninsula to be around 35 km based on the depth where a high-velocity anomaly is observed. The SV-wave velocity model shows prominent fast S-velocity anomalies near northeastern Japan, associated with the subducting Pacific plate. Low-velocity anomalies are found beneath the east coast of the Korean peninsula at 100 km depth, which may play a role in the formation of the Ulleungdo and the Ulleung basin. We observed low-velocity anomalies beneath the Yamato basin at 100 km depth as well, which may indicate the upwelling of fluid from the Pacific plate via dehydration at deeper depth.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.36-43
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• 2013

Aralia elata Seem. have a typical traditional significance among the wild herbs traditionally. Edible shoots of A. elata will augment consumer's interest due to its high value functional value, eco-friendly and pesticide-free produce. A. elata's root, fruit and bark are used as material of hypoglycemic agent and medicine for diabetes, kidney trouble, acute hepatitis, rheumation arthritis, stomach cancer and gastroenteric trouble. Flavonoid glycoside compound which is separated from A. elata's shoot shows high antioxidative activity. Also, root's identified active materials of antimicrobial was reported to be produced as food preservative and handy antimicrobial. Therefore, this research investigated quantitative morphological characteristics of leaves, spine and bud in naturally dominated and introducted A. elata in south Korea and then considered its principal compound analysis(PCA) and classification analysis(CA) among the 6 improved cultivars and 19 clones. PCA results showed that it show 76% accumulated explanation from four PC. The A. elata clones were classified into five groups; the first group of 15 clones including Yeongok, the second group of 5 clones including Yeoju, the third group of Bonghwa, Ulleung, the fourth group of Yongmunsa, Boseong and the fifth group of Singu. The object of this study will give us invaluable information about breeding by selection of A. elata in south Korea.

• Journal of the Korean earth science society
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• v.27 no.6
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• pp.620-642
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• 2006

The Moho structure and its deformation in the southern part of the Korean Peninsula were estimated using gravity and topography data. Gravity signals from the upper and lower crust were separated using a filter that was computed from isostacy and elastic thickness. The result of this study shows three characteristic features of the Moho deformation. First, the Moho folding structure is parallel to SKTL (the South Korean Tectonic Line), which indicates positive association with the collision of the Yeongnam and Gyeonggi Massifs and repeated compression afterwards. In contrast, noticeable deformation of the Moho was not observed along the Imjingang Belt, which is interpreted as another continental collisional belt in the Korean Peninsula. Second, the Moho beneath the Gyeongsang Basin has remarkably risen; this seems to be the result from both the collisional compression and buoyancy caused by magmatic underplating. Third, the Moho deformation is shallowest in the east of the Taebaek Mountains and deepens toward the west, consistent with the topographic characteristic of the Korean Peninsula of "high east and low west". It can be interpreted as the results of the opening of the East Sea and Ulleung Basin. A tectonic explanation for this could be the ascent of the mantle induced by continental rifting and horizontal extension at the early stage of the opening of the East Sea. The Moho deformation model computed in this study correlates well with the earthquake distribution and crustal movement measured by GPS. We suggest that the compression along the SKTL is still exerted, consequently, the Moho deformation is active, although it may be weak.

• Geophysics and Geophysical Exploration
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• v.12 no.2
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• pp.173-182
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• 2009

In April 2008, KIGAM carried out an ocean-bottom seismometer (OBS) survey in the central Ulleung Basin where strong bottom simulating reflectors (BSRs) were revealed from previous surveys and some gas-hydrate samples were retrieved by direct sampling. The purpose of this survey is to estimate the velocity structure near the BSR in the gas hydrate prospect area using wide-angle seismic data recorded on the ocean-bottom seismometers. Along with the OBS survey, a 2-D seismic survey was performed whereby stratigraphic and preliminary velocity information was obtained. Two methods were applied to wide-angle data for estimating P wave velocity; one is velocity analysis in the $\tau$-p domain and the other is seismic traveltime inversion. A 1-D interval velocity profile was obtained by the first method, which was refined to layered velocity structure by the latter method. A layer stripping method was adopted for modeling and inversion. All velocity profiles at each OBS site clearly show velocity reversal at BSR depths due to the presence of gas hydrates. In addition, we could confirm high velocity in the column/chimney structure.

• 한국해양학회지
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• v.30 no.5
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• pp.493-511
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• 1995

Analysis of the Late Quaternary benthic foraminifera in the cores from the western part of the East Sea, Korea, indicates several distinct changes in the paleoenvironments during the deposition. The palecology of biofacies of Cores PC-1 from the upper slop and PC-2 from the rise shows several distinct changes in bottom water temperatures during the late Quaternary. The Core PC-4 from the Ulleung Basin generally consists of agglutinated genus, Muiliammina, and anaerobic calcareous genus, Bolivina, in biofacies, suggesting that the anoxic bottom condition was prevailed during the deposition. Benthic foraminiferal rare or barren zones in the Cores indicate the limits of water circulation caused by lower sea-level in the regions during the glacial period through the Late Quaternary. The changes of benthic foraminiferal biofacies reflect temporal and spacial variations in overall bottom environments, such as bottom water temperature, dissolved oxygen, and water circulation pattern. The benthic foraminiferal data can be used to interpret paleoclimatic conditions and predict global sea-level changes, and the results of these studies should be useful to understand the evolutional history of the East Sea through the Late Quaternary.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.3
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• pp.170-179
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• 1999

The SUS (Signal, Underwater Sound)-OAT experiment was carried out in the Ulleung Basin of the East Sea on 3 June 1997. The SUS-OAT system consisted of aircraft deployed shots as sources and a vertical line array (VLA) tethered by a receiver ship was used to survey a large area where a mesoscale warm eddy appears frequently. The experiment was carried out such that explosive charges set to detonate at 800 ft depth were dropped in a rectangular ($120{\times}120$ km). Sources were a rapidly deployable SUS charge (MK 61 MOD 0), and receiver is a fixed VLA, 90 m in length (150-240 m in receiver depth), composed of 10 elements equally spaced. The reference ray paths are computed by range-dependent acoustic model in canonical ocean based on the historical data. The singular value decomposition (SVD) method is used to obtain the horizontal perturbation of the temperature fields. Horizontal distributions of temperature fields at 150 m and 200 m depth show a weak warm eddy observed by AXBT and the inversely estimated temperature shows similar patterns in terms of the location of the warm eddy. In conclusion, the SUS-OAT experiment has been successful to estimate the position of warm eddy and its temperature field in the East Sea of Korea.