• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.4
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• pp.33-43
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• 2005

China Coastal Waters(CCW) usually appeared from June through October every years, and it appeared very strong in August. In the harmonic analysis for Sea level anomaly (SLA), the annual amplitude of the eastern part (8~9.5cm) in Jeju Island was lower than those of the western part (over 13cm). In the harmonic analysis for Sea Surface Temperature (SST), the annual amplitude of the eastern part($7{\sim}8.5^{\circ}C$) in Jeju Island was lower than those of the western part($5.5{\sim}6^{\circ}C$). For the Power Spectrum Density (PSD), SLA and SST remarkablely peaked on the annual period, semi-annual period and 3-monthly period. In summer and autumn, SLA of 1996 to 1999 was high in comparison to other years, and then it should be considered that the appearance of CCW was closely related to heavy rainfalls. The path of CCW formed this boundary of temperature between the yellow sea and the east china sea.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.383-386
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• 2005

CCW(China Coastal Water) is different each year. It appears clearly from June to October in the neighboring sea of Jeju island. It appears in June, and it's strong most in August, after tat disappears in October. CCW appeared clearly at 1996 and 1999 during investigation period(1995 to 1999). SLA and SST appear annual variations(about 365day), semi-annual variations(about 180day) from power spectral density. After PCA(Principal component analysis), it's different. PCA of SLA shows 43day variations and PCA of SST shows 259day variations. SLA and SST appear annual variation, semi-annual variation and seasonal variation from power spectral density. SLA appeared that summer and fall of 1996 and 1999 is higher than other years. It seem to be being the relationship which is close with the severe rain strom. Temperature distribution of sea surface according to season is different, but clearly water temperature boundary divides this area into Yellow Sea and East China Sea. It considered that CCW follow according to boundary of temperature. The variation which it follows at time of SLA and SST is faster about one month to three month at Yangtz.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.4
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• pp.195-204
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• 2009

In order to estimate sea surface current fields in the East Sea, we examined characteristics of mean dynamic topography (MDT) fields (or mean surface current field, MSC) generated from three different methods. This preliminary investigation evaluates the accuracy of surface currents estimated from satellite-derived sea level anomaly (SLA) data and three MDT fields in the East Sea. AVISO (Archiving, Validation and Interpretation of Satellite Oceanographic data) provides a MDT field derived from satellite observation and numerical models with $0.25^{\circ}$ horizontal resolution. Steric height field relative to 500 dbar from temperature and salinity profiles in the East Sea supplies another MDT field. Trajectory data of surface drifters (ARGOS) in the East Sea for 14 years provide another MSC field. Absolute dynamic topography (ADT) field is calculated by adding SLA to each MDT. Application of geostrophic equation to three different ADT fields yields three surface geostrophic current fields. Comparisons were made between the estimated surface currents from the three different methods and in-situ current measurements from a ship-mounted ADCP (Acoustic Doppler Current Profiler) in the southwestern East Sea in 2005. For offshore areas more than 50 km away from the land, the correlation coefficients (R) between the estimated versus the measured currents range from 0.58 to 0.73, with 17.1 to $21.7\;cm\;s^{-1}$ root mean square deviation (RMSD). For coastal ocean within 50 km from the land, however, R ranges from 0.06 to 0.46 and RMSD ranges from 15.5 to $28.0\;cm\;s^{-1}$. Results from this study reveal that a new approach in producing MDT and SLA is required to improve the accuracy of surface current estimations for the shallow costal zones of the East Sea.

• 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.

• Journal of Environmental Science International
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• v.17 no.4
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• pp.461-468
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• 2008

Competitive power of pelagic fishery in Korea has been weakened by the domestic and international problems such as wage increase and exclusive economic zone. To make it worse, fishing fleet spends more than 80% of fishing time on searching fishing grounds. Real-time information on oceanographic data, temperature in particular, are likely to contribute to raise efficiency of fishing. However, available data obtained by satellite remote sensing, fixed buoy and drifting buoy, limited to sea surface or fixed positions. ARGO (Array for Real-time Geostrophic Oceanography), an international program, has delivered vertical profiles of temperature and salinity in the upper 2000m of the world ocean every 10 days using freely moving floats. We have developed real-time oceanographic information system for pelagic fishery based on the Argo data which has the contents of vertical profile, horizontal distribution and vertical section of temperature around fishing grounds and searched data can be download unrestrictedly. Comparison of skipjack catch with sea surface temperature and depth of $20^{\circ}C$ derived from Argo data in the West Equatorial Pacific revealed that Argo data are able to help fishing fleet to find fishing grounds and to increase catch.

• Ocean and Polar Research
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• v.33 no.1
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• pp.1-11
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• 2011

This study describes measurements of fast ice recorded on May 23, 2009, in Kongsfjorden (translated as 'Kongs Fjord'), an inlet on the west coast of Spitsbergen in the Svalbard Archipelago. Seasonal fast ice is an important feature for Svalbard fjords, both in relation to their physical environment and also the local ecosystem, since it grows seaward from the coast and remains in place throughout the winter. Ice thickness, snow, ice properties, and wind speed were measured, while SAR (Synthetic Aperture Radar) data was observed simultaneously observed two times from ALOS-PALSAR (L-band). Measured ice thickness was about 25-35 cm while the thickness of ice floe broken from fast ice was measured as 10-15 cm. Average salinity was 1.9-2.0 ppt during the melting period. Polarimetric data was used to extract H/A/alpha-angle parameters of fast ice, ice floe, snow and glacier, which was classified into 18 classes based on these parameters. It was established that the area of fast ice represents surface scattering which indicates low and medium entropy surface scatters such as Bragg and random surfaces, while fast ice covered with snow belongs to a zone of low entropy surface scattering similar to snow-covered land surfaces. The results of this study will contribute to various interpretations of interrelationships between H/A/alpha parameters and the wave scattering Phenomenon of sea ice.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.95-95
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• 2011

토양수분은 전 지구 및 기후 모델 연구, 전 지구 환경 감시, 기후변화, 대기-지표의 물과 에너지 상호교환 등 중요한 역할을 한다. 최근에는 수동형 마이크로웨이브 센서를 이용하여 토양수분을 탐지하고 있으며, NASA는 공식적인 전구 토양수분을 제공하고 있다. 특히, AMSR-E(Advandced Microwave Scanning Radiometer on EOS)의 6 GHz 영역에서 산출된 토양수분은 지표 토양층(0～5 cm)의 높으 정확도의 토양 수분 정보를 제공하고 있다. 지금까지의 위성관측을 이용한 토양 수분 알고리즘은 복잡한 선행모델과 관측된 경험식을 바탕으로 한다. 이 연구의 제안한 알고리즘은 위성에서 관측된 휘도온도 정보를 이용하여 역변환 방법을 이용하여 토양수분을 산출할 수 있기에, 복잡한 선행모델 사용을 최소화하는 장점이 있다. 본 연구에서 제시한 토양수분 산출 알고리즘은 각 채널(6.9 및 37 GHz)의 특성을 이용하여 거친 표면의 반사도를 산출한 후, 편광비율 특성을 이용한다. 아울러 반사도는 Hong 근사식을 이용하여 지표면 거칠기, 물질의 특성을 나타내는 유전상수를 산출하고 두 변수 사이의 관측된 경험적 관계식를 이용하여 전 지구적인 토양수분이 산출한다. 이 결과는 NASA에서 산출한 토양 수분과 현장관측 (SMEX03)의 오클라호마, 조지아 지역 관측 결과와 비교하였을 때, 사용자들이 요구하는 수준 (<0.06g/$cm^3$)의 정확도를 만족시킨다. 본 연구에서 제시된 토양수분 알고리즘은 단순성, 정확성, 물리적 기반을 바탕으로 하기에 현업용으로 그 활용 가치가 높다. 본 연구 결과는 향후 국외 토양수분산출 전용 위성들인 SMOS(Soil Moisture and Ocean Salinity)와 SMAP(Soil Moisture Active/Passive) 자료들을 생산하는데 활용된다면, 전 지구적 토양수분 정보제공에 기여할 수 있을 것으로 예산된다.

• Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.117-124
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• 2013

We investigated the short-term and local changes in the thermohaline front in the Jeju Strait, Korea, which is usually formed during winter and spring. To do so, we compared Real-Time Observation System by Ferryboat (RTOSF) data with wind data and routinely collected oceanographic data. During February and April 2007, a thermohaline front formed in the Jeju Strait around the 13-$14^{\circ}C$ isotherms and 33.0-33.5 isohalines. The thermohaline was clearly weakened and began moving southward in mid-March. The variations in the surface temperature and salinity showed a continuous north-south oscillation of the thermohaline front with a period of 3-10 days. The speed of the short-term and local fluctuation of thermohaline front was about 5-30 cm/s. We confirmed these findings by examining the variation in the maximum temperature gradient and $14^{\circ}C$ isotherm during the study period. These short-term and local changes had not been previously detected using serial oceanographic and satellite data. Analysis of local wind data revealed a northerly wind fluctuation with a period of 3-10 days, which was clearly related to the short-term and local changes in the thermohaline front. The short-term and local changes of the thermohaline front in the Jeju Strait originated from local changes in the winter monsoon in this area.

• Korean Journal of Remote Sensing
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• v.36 no.1
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• pp.41-53
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• 2020

The production of near- and off-shore fisheries in South Korea is decreasing due to rapid changes in the fishing environment, particularly including higher sea temperature in recent years. To improve the competitiveness of the fisheries, it is necessary to provide fish catch information that changes spatiotemporally according to the sea state. In this study, artificial intelligence models that predict the CPUE (catch per unit effort) of mackerel, anchovies, and squid (Todarodes pacificus), which are three major fish species in the near- and off-shore areas of South Korea, on a 15-km grid and daily basis were developed. The models were trained and validated using the sea surface temperature, rainfall, relative humidity, pressure,sea surface wind velocity, significant wave height, and salinity as input data, and the fish catch statistics of Suhyup (National Federation of Fisheries Cooperatives) as observed data. The 10-fold blind test results showed that the developed artificial intelligence models exhibited accuracy with a corresponding correlation coefficient of 0.86. It is expected that the fish catch models can be actually operated with high accuracy under various sea conditions if high-quality large-volume data are available.