• Journal of the Korean earth science society
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• v.39 no.2
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• pp.139-153
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• 2018

The sea surface wind field has long been obtained from satellite scatterometers or passive microwave radiometers. However, the importance of satellite altimeter-derived wind speed has seldom been addressed because of the outstanding capability of the scatterometers. Satellite altimeter requires the accurate wind speed data, measured simultaneously with sea surface height observations, to enhance the accuracy of sea surface height through the correction of sea state bias. This study validates the wind speeds from the satellite altimeters (GFO, Jason-1, Envisat, Jason-2, Cryosat-2, SARAL) and analyzes characteristics of errors. In total, 1504 matchup points were produced using the wind speed data of Ieodo Ocean Research Station (IORS) and of Korea Meteorological Administration (KMA) buoys at Marado and Oeyeondo stations for 10 years from December 2007 to May 2016. The altimeter wind speed showed a root mean square error (RMSE) of about $1.59m\;s^{-1}$ and a negative bias of $-0.35m\;s^{-1}$ with respect to the in-situ wind speed. Altimeter wind speeds showed characteristic biases that they were higher (lower) than in-situ wind speeds at low (high) wind speed ranges. Some tendency was found that the difference between the maximum and minimum value gradually increased with distance from the buoy stations. For the improvement of the accuracy of altimeter wind speed, an equation for correction was derived based on the characteristics of errors. In addition, the significance of altimeter wind speed on the estimation of sea surface height was addressed by presenting the effect of the corrected wind speeds on the sea state bias values of Jason-1.

• Journal of Environmental Science International
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• v.18 no.7
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• pp.721-733
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• 2009

To examine the fluctuations of aerosol number concentration with different size in the boundary layer of marine area during summer season, aerosol particles were assayed in the Ieodo Ocean Research Station, which is located 419 km southwest of Marado, the southernmost island of Korea, from 24 June to 4 July, 2008. The Laser Particle Counter (LPC) was used to measure the size of aerosol particles and NCEP/NCAR reanalysis data and sounding data were used to analyze the synoptic condition. The distribution of aerosol number concentration had a large variation from bigger particles more than 3 ${\mu}m$ in diameter to smaller particles more than 1 ${\mu}m$ in diameter with wind direction during precipitation. The aerosol number concentration decreased with increasing temperature. An increase (decrease) of small size of aerosol (0.3${\sim}$0.5 ${\mu}m$ in diameter) number concentration was induced by convergence (divergence) of the wind fields. The aerosol number concentration of bigger size more than 3 ${\mu}m$ in diameter after precipitation was removed as much as 89${\sim}$94% compared with aerosol number concentration before precipitation. It is considered that the larger aerosol particles would be more efficient for scavenging at marine boundary layer. In addition, the aerosol number concentration with divergence and convergence could be related with the occurrence and mechanism of aerosol in marine boundary layer.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.1
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• pp.11-19
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• 2002

We studied the characteristics of catch fluctuation and distribution of yellow tail resources in Korean Waters from 1991 to 2000. The obtained results are summarized as follow, The distribution of yellow tail resources in Korean Waters was showed by mooving north-ward groups from Spring to Autumn and south-ward groups from Autumn to Winter with they passed Winter and spawned from the south of Jeju Island and Tsushima current. Therefore, the fishing ground of yellow tail by handline fishing around Marado targets a school of yellow tails which migrate south-ward so as to winter and spawn.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.845-852
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• 2003

This study deals with the relationship between the red tide occurrence and the meteorological and marine factors, the prediction of areas where the red tide is likely to occur based on the information, and the satellite monitoring for the red tide in mid-South Sea of Korea. From 1990 to 2001, the red tide was observed every year and the number of occurrences increased as well. The red tide mostly occurred in July, August, and September. The most important meteorological factor governing the mechanisms of the increase in the number of red tide occurrences is found to be a heavy precipitation. It was found that the favorable marine environmental conditions for the red tide formation are some of marine factors such as the warm water temperature, the low salinity, the high suspended solid, the low phosphorus, and the low nitrogen. The necessary conditions for the red tide occurrence are found to be the heavy precipitation (23.4-54.5 mm) for 2∼4 days, the warm temperature $(24.6∼25.9^{\circ}C)$, proper sunshine (2∼10.3 h), and light winds (2∼4.6 m/s & SW) for the day in red tide occurrence. It was possible to monitor the spatial distributions and concentration of the red tide using the satellite images. It was found that the likely areas for red tide occurrence in August 2000 were Yosu - Dolsan coast, Gamak bay, Namhae coast, Marado coast, Goheung coast, and Deukryang bay.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.323-328
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• 2003

This study deals with the relationship between the red tide occurrence and the meteorological and marine factors, the prediction of areas where the red tide is likely to occur based on the information, and the satellite monitoring for the red tide in mid-South Sea of Korea. From 1990 to 2001, the red tide was observed every year and the number of occurrences increased as well. The red tide mostly occurred in July, August, and September. The most important meteorological factor governing the mechanisms of the increase in the number of red tide occurrences is found to be a heavy precipitation. It was found that the favorable marine environmental conditions for the red tide formation are some of marine factors such as the warm water temperature, the low salinity, the high suspended solid, the low phosphorus, and the low nitrogen. The necessary conditions for the red tide occurrence are found to be the heavy precipitation (23.4∼54.5 mm) for 2∼4 days, the warm temperature (24.64-25.85 $^{\circ}C$), proper sunshine (2∼10.3 h), and light winds (2∼4.6 m/s & SW) for the day in red tide occurrence. It was possible to monitor the spatial distributions and concentration of the red tide using the satellite images. It was found from this study that the likely areas for red tide occurrence in August 2000 were Yosu ∼ Dolsan coast, Gamak bay, Namhae coast, Marado coast, Goheung coast, and Deukryang bay.

• Atmosphere
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• v.22 no.1
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• pp.97-107
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• 2012

To investigate variation of aerosol number concentration at each different size with three-dimensional (3D) wind components in ocean area, aerosol particles and 3D wind components were measured in the Ieodo Ocean Research Station, which is located to 419 km southwest from Marado, the southernmost island of Korea, from 25 June to 8 July 2010. The Laser Particle Counter (LPC) and ultrasonic anemometer were used to measure the size of aerosol particles and 3D wind components (zonal (u), meridional (v), and vertical (w) wind) respectively. Surface weather chart, NCEP/NCAR reanalysis data and sounding data were used to analyze the synoptic condition. The distribution of aerosol number concentration had a large variation from bigger particles more than 1.0 ${\mu}m$ in diameter by wind direction during precipitation. In the number concentration of aerosol particles with respect to the weather conditions, particles larger than 1.0 ${\mu}m$ in size were decreased and sustained to the similar concentration at smaller particles during precipitation. The increase in aerosol number concentration was due to the sea-salt particles which was suspended by southwesterly and upward winds. In addition, the aerosol number concentration with vertical wind flow could be related with the occurrence and increasing mechanism of aerosol in marine boundary layer.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.47-53
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• 2004

For the purpose of comparison between the designed coverage and actual coverage of Korean DGPS (Differential Global Position System) beacon stations, we have received the ship‘s positions with states and IDs of their stations on the navigation route of Jeju-Tianjin by automatic selection mode of DGPS receiver and on them of Jeju-Inchun and Jeju-Vladibostok by manual mode. Also in case that some obstructions were on propagation routes from DGPS beacon stations to receiving positions, a restriction on available ranges of DGPS beacon signals was investigated. The results obtained are as follows : 1. The coverage of Korean DGPS beacon stations was designed 100NM (Nautical mails) at 40.0dB(over ${\mu}$V/m). But the actual coverages of them according to their stations and propagation routes were 0.3-3.6 times as wide as designed coverage. 2. In case that the propagation route of beacon signals from DGPS beacon stations was on the sea, the propagation distance of north direction from the stations was longer than south direction. 3. The coverages of Echongdo and Ulungdo stations were 366NM on the yellow sea and 342.3NM on the east sea of Korea respectively, and were widest than any other stations. 4. The coverage of Marado station on the south and yellow seas of Korea was very unstable because of the Halla mountain on the propagation route. Maximum receiving range to be measured by automatic selection mode of DGPS receiver was 145NM on the route of Jeju-Tianjin on June 22-July 1, 2002. Minimum receiving range to be not measured by manual selection mode was 28.7NM on the route of Jeju-Inchun on June 26-28, 2003

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.212-219
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• 2019

This study was conducted to investigate marine algal community characteristics and the status of barren ground in the summer at study sites on Jeju Island, Korea. Sampling was carried out from July to September 2017 using a qualitative and quantitative survey (including coverage of non-geniculated coralline algae and density of grazer) by scuba diving. A total of 121 species were identified, including 11 (9.1 %) green algae, 24 (19.8 %) brown algae, and 86 (71.1 %) red algae. Hyeongjeseom had the greatest diversity, with 60 species, and Harye the least, with 18 species. The mean biomass at the study sites was $1,503.0g{\cdot}m^{-2}$, while the mean for the neighboring islets ($3,268.7g{\cdot}m^{-2}$) was higher than that of the main island ($914.7g{\cdot}m^{-2}$). Also, dominant species was identified: Sargassum macrocarpum at the neighboring islets, and Ecklonia cava at the main island, with differences showing not only in biomass but also species composition. In conclusion, the marine algal community status in summer at the study sites was evaluated based on the algal community characteristics (species composition, biomass, biomass ratio of kelp species), coverage of non-geniculated coralline algae, and density of grazer. As a result, both Hyeongjeseom and Marado require preservation and management to maintain their excellent marine algal communities, and other sites on the main island require the creation and/or restoration of marine algal communities. In addition, as the generation of barren ground accelerates, it is urgent not only to grasp existing monitoring research but also to identify the status of the marine algal community where it is not known at present.

• Journal of the Korean earth science society
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• v.33 no.3
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• pp.259-268
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• 2012

To investigate the fluctuation of marine aerosol number concentration at each different size with vertical winds in ocean area, aerosol particles and vertical wind components were measured in the Ieodo Ocean Research Station, which is located to 419 km southwest of Marado, the southernmost island of Korea, from 8 to 22 June 2009. The Laser Particle Counter (LPC) and ultrasonic anemometer were used to measure the number of aerosol particles and vertical wind speed. Surface weather chart, NCEP/NCAR reanalysis data and sounding data were used to analyze the synoptic condition. The distribution of aerosol number concentration had a large fluctuation of bigger particles more than 1.0 ${\mu}m$ in diameter by vertical wind speed during precipitation. The aerosol particles larger than 1.0 ${\mu}m$ in diameter increased as the wind changed from downward to upward during precipitation. The aerosol number concentration of bigger size than 1.0 ${\mu}m$ in diameter increased about 5 times when vertical velocity was about 0.4 $ms^{-1}$. In addition, the accumulation and coarse mode aerosol number concentration decreased about 45% and 92%, respectively compared to concentrations during precipitation period. It is considered that vertical wind plays an important role for the increasing of coarse mode aerosol number concentration compared to the large aerosol particles sufficiently removed by the scavenging effect of horizontal winds. Therefore, the upward vertical winds highly contribute to the formation and increase in aerosol number concentration below oceanic boundary layer.