• Economic and Environmental Geology
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• v.45 no.1
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• pp.41-48
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• 2012

A theoretical $CO_2$ storage capacity is estimated on the southwestern continental shelf margin of Ulleung Basin, offshore Korea using 2D/3D multi-channel seismic and wellbore data acquired in the area over the two decades since the late 1980s. For the first time in Korea, the present study applies an efficiency factor to the capacity calculation, together with the other required parameters. For possible $CO_2$ storage volume estimation of the study area, we interpreted the seismic data in the Gorae area from 800 m to 3,000 m below the seafloor integrated with the well data, and identified five different seismic units; the limited depth interval is considered because of fluid state of $CO_2$ and tightness of the formation. The total volumes of each seismic unit were converted with a time-depth relation inferred from the checkshot surveys before the other required parameters including porosity and density were applied to compute the potential storage capacity. The accumulated possible storage volume from the five depositional units in the study area is estimated to be approximately 5,100 Mton ($P_{50}$). The approaches made in this study will be applied to the rest area of the basin and other continental shelves (i.e., Yellow Sea and northern part of East China Sea) in the next phase.

• Atmosphere
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• v.25 no.3
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• pp.435-447
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• 2015

This study explores the synoptic characteristics of cold days over South Korea and their relationship with large-scale climate variability. The cold day, which is different from cold surge, is defined when daily-mean surface air temperature, averaged over 11 KMA stations, is colder than 1-percentile temperature in each year by considering its long-term trend over 1960~2012. Such event is detected by quantile regression and the related synoptic patterns are identified in reanalysis data. Composite geopotential height anomalies at 500 hPa show that cold days are often preceded by positive anomalies in high latitudes and negative anomalies in midlatitudes on the west of Korea. While the formers are quasi-stationary and quasi-barotropic, and often qualified as blocking highs, the latters are associated with transient cyclones. At cold days, the north-south dipole in geopotential height anomalies becomes west-east dipole in the lower troposphere as high-latitude anticyclone expands equatorward to the Northern China and mid-latitude cyclone moves eastward and rapidly develops over the East Sea. The resulting northerlies cause cold days in Korea. By performing composite analyses of large-scale climate indices, it is further found that the occurrence of these cold days are preferable when the Arctic Oscillation is in its negative phase and/or East Asian monsoon circulation and Siberian high are anomalously strong.

• 한국해양학회지
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• v.29 no.4
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• pp.357-365
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• 1994

The sediments on the continental shelf off the west coast (middle part) of Korea are divided into northern sandy deposits and southern muddy sediments, respectively. The sandy sediments consist dominantly of quartz and feldspar grains, representing mature-stage sediment in composition. Further-more, the presence of iron-stained quartz grain and glauconite does indicate that the sediments are similar to the relict sediments on the outer shelf of Yellow Sea and East China Sea. These sandy sediments are interpreted as a basal sands that were deposited during the transgression period due to sea-level rise after to last glacial maximum (LGM). The tidal deposits in the Namyang Bay, the west coast of Korea are divided vertically into the upper layer of muddy sediments and the lower layer of sandy sediments. the upper layer sediments contain abundant rock fragments, and are interpreted as the modern tetragenous sediments. The lower layer sediments, on the other hand, are rich in quartz and feldspar grains, representing high index of sediment maturity ratio. the lower layer sandy deposits show the presence of iron-stained.

• Journal of the Korean earth science society
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• v.43 no.2
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• pp.265-282
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• 2022

This study analyzes the impact of long-range transport of biomass burning emissions from northeastern China on the concentration of particulate matter of diameter less than 10 ㎛ (PM₁₀) in Korea using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). Korea was impacted by anthropogenic emissions from eastern China, dust storms from northern China and Mongolia, and biomass burning emissions from northeast China between April 4-and 7, 2020. The contributions of long-range PM₁₀ transport were calculated by separating biomass burning emissions from mixed air pollutants with anthropogenic emissions and dust storms using the zeroing-out method. Further, the radiation energy budget over land and sea around the Korean Peninsula was analyzed according to the distribution of biomass burning emissions. Based on the WRF-Chem simulation during April 5-6, 2020, the contribution of long-range transport of biomass burning emissions was calculated as 60% of the daily PM₁₀ average in Korea. The net heat flux around the Korean Peninsula was in a negative phase due to the influence of the large-scale biomass burning emissions. However, the contribution of biomass burning emissions was analyzed to be <45% during April 7-8, 2020, when the anthropogenic emissions from eastern China were added to biomass burning emissions, and PM₁₀ concentration increased compared with the concentration recorded during April 5-6, 2020 in Korea. Furthermore, the net heat flux around the Korean Peninsula increased to a positive phase with the decreasing influence of biomass burning emissions.

• Journal of Digital Convergence
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• v.16 no.3
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• pp.275-289
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• 2018

It is necessary to develop a bridgehead port for trading with northern countries to promote trade through the East Sea because the East Sea Rim economic bloc around the Northeast Asia including South Korea, China, Russia, Japan, and North Korea has a high growth potential in the future. Therefore, this study aims to suggest a strategic direction to enhance the competitiveness of Donghae Port through reinforcement of container cargoes by conducting Importance-Performance Analysis (IPA) for stakeholders of Donghae Port. The analysis results suggest that it is necessary to improve the five evaluation factors: attractiveness of container and bulk volumes, appropriate ratio of export/import container quantities, frequency of vessel entry and diversity of sea routes, convenience of complex linked transportation, and competitiveness of cargo handling equipment. The implications of this study are as follows. First, it is necessary to continuously research the current status of container and bulk cargo volumes of the port and ways to increase the absolute cargo volume. Second, we need to consider realistic alternatives to improve the ratio of export/import container quantities. Third, in terms of network, we should establish a service improvement plan to increase the frequency of port calls and the diversity of sea routes. Furthermore, incentives should be provided to increase the trade volume of Donghae Port through strengthened complex linked transportation function. Finally, it is urgently necessary to provide investment support for container handling equipment as an essential requirement for the activation of the container cargoes in Donghae Port.

• Korean Journal of Plant Resources
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• v.27 no.2
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• pp.183-187
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• 2014

Hovenia dulcis var. koreana Nakai, the oriental raisin tree, has been considered not only fruit but an herbal medicine in East Asia including Korea, Japan and east China. As honey plant, value of this species had been rising steadily. The aim of this study was conducted to develop the propagation technique by scion collection time, scion age and vinyl house on survival rate of H. dulcis. The survival rate by veneer grafting showed no significant differences among 3 new cultivars. The scion collection at the northern temperature zone was observed to be the most appropriate time before the spring equinox when the plants are fully dormant. Especially, the installation of vinyl house showed 86% survival rate by veneer grafting. The scion age was effective 1 year shoot than 2 years shoot for increase the grafting survival rate. In this case, the installation of vinyl house can contribute above 80%.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.3
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• pp.139-150
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• 2003

There was a close relationship between spatio-temporal distribution of Cochlodinium polykrikoides red tide and meso-scale variation of oceanographic environment around the Korean waters. Oceanographic conditions of Narodo island, where red tide usually first occurred during summer seasons were formation of the thermohaline frontal zone from 1995 to 2001. Huge C. polykrikoides red tides were observed in every uneven year during the past 7 years (1995~2001) and quasi-biennial oscillation also occurred in the oceanographic variations of sea surface temperature and salinity in the northern part of the East China Sea during the same years. The distribution area and moving pattern of C. polykrikoides red tides were definitely depended on the temporal and spatial variation of upwelling cold water originated form the southeastern coast of the Korean peninsula in summer season.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.1
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• pp.17-24
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• 2009

This study was conducted to find out the effects of relationship between ocean-meteorological factors and snowfall at Incheon, Gunsan and Mokpo when cold and dry continental air mass passed through the West Sea of Korea in winter. Mean snowfall from December to February showed the order of Gunsan (12.7 cm), Mokpo (9.0 cm) and Incheon (7.8 cm). In particular, the snowfall in the three regions showed the regional difference in December and February. It was well consistent with the extension of continental high. Extension of continental high can cause effect on snowfall at the west regions (Inchoen, Gunsan, Mokpo) of the Korean Peninsula. The continental high extended from the southern China to western coastal region of the Korean Peninsula in December, it extended from the northern China to central area of the Korean Peninsula in January. It also extended from the north side of China through Bohai Sea and Yodong Peninsula to central area of the Korean Peninsula in February. Therefore, more snowfall recorded in Incheon is higher in February than December whereas Gunsan and Mokpo is the opposite. The heavy snowfall at the three regions was caused by loss of the heat from the ocean to air when the heat loss was higher than 100 $W/m^2$. The heavy snowfall was also observed when the arrangement of continental high atmospheric pressure and low pressure was high at the west and low at the east, which formed a front in West and when the wind blow from the North or North West at the speed of 4${\sim}$8 m/sec.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.2
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• pp.117-134
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• 1998

The study on the Assembling Mechanism of the Hairtail, Trichiurus lenpturus, at the Fishing Grounds of the Cheju Strait had been investigated by analyzing the relationship of the oceanographic conditions and the fishing ground of the Hairtail in the Cheju Strait. 1. The fishing grounds of the hairtail at the Cheju Strait are formed at the bottom of a high temperature of the tidal front at the coast. area of northern Cheju Island, the tip of the linguiform is high in salinity at the eastern and western entrances of Cheju Island, low salinity eddy on the surface and its surrounding front, various water masses in the Strait and coastal waters of the South Sea in Korea. 2. The fishing grounds of the Hairtail at the Cheju Strait begins with the sea surface temperature higher than $15^{\circ}C$ and the incoming of low salinity water now from the East China Sea. 3. Estimation of optimum temperature and salinity per season based upon analysis for relationship between temperature of water and salinity of the bottom layer and the catch is : 15.2~$16.4^{\circ}C$, 34.20~34.40${\textperthousand}$ in spring(June); 14.4~ $17.0^{\circ}C$, 33.70~34.30${\textperthousand}$ in summer(July~September); and 15.7~ $18.6^{\circ}C$, 33.70~34.50$\textperthousand$ in autumn(October~December). Hairtail are mostly caught at the Yellow Sea Warm Current and Tsushima Current with temperature over $14.5^{\circ}C$ and salinity over 33.70${\textperthousand}$ at the bottom layers of the Cheju Strait. 4. Considering the relationship between the amount of hairtail catch and the water temperature of bottom layer, when the bottom water being above $14.0^{\circ}C$ flowed into Cheju Strait through the western entrance of the strait in summer, the ca-h appears to have been abundant. In contrast, the catch has been poor when the temperature of such water was recorded to be below $13^{\circ}C$ Therefore, distribution patterns of water at the bottom layer can be used as a forecast index whether the catch of a certain year will be good or poor.

• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.299-304
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• 2005

Geoid undulation and gravity anomaly were calculated from GRACE satellite data on the eastern Asia including Korean peninsula. Geoid undulation varies from -60m in the China to 60m toward the Pacific Ocean across the Korean Peninsula. Calculated gravity anomalies are in the range of -60 and 60 mgal except the subduction zone showing -100 mgal. High positive values are observed at Mt. Baekdu, Kaema highland and Taebaek mountains, and low values at Ulleung, Japan and Yamato basins in the East sea. We removed regional components below the spherical harmonic degree of 10 from gravity anomaly to get the residual anomaly for crust components. Residual gravity anomaly shows high anomalies at the northern mountainous area and Kyungsang basin in the Korean Peninsula. And low anomalies appears at the western Korea bay basin, Kunsan basin, Cheju basin, and Ulleung basin in the marine. Anomalies separated by the spherical harmonic degree as well as the residual anomalies are useful for the study of large crustal structure about geologic scale and depth distribution and for the survey of natural resources.