• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• 제22권3호
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• pp.57-68
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• 2017

Continuous monitoring of spatial and temporal changes in key marine environmental parameters such as SST (sea surface temperature) near IORS (Ieodo Ocean Research Station) is demanded to investigate the ocean ecosystem, climate change, and sea-air interaction processes. In this study, we aimed to develop the system for continuously measuring SST using a TIR (thermal infrared) sensor mounted at the IORS. New SST algorithm is developed to provide SST of better quality that includes automatic atmospheric correction and emissivity calculation for different oceanic conditions. Then, the TIR-based SST products were validated against in-situ water temperature measurements during May 17-26, 2015 and July 15-18, 2015 at the IORS, yielding the accuracy of 0.72-0.85 R-square, and $0.37-0.90^{\circ}C$ RMSE. This TIR-based SST observing system can be installed easily at similar Ocean Research Stations such as Sinan Gageocho and Ongjin Socheongcho, which provide a vision to be utilized as calibration site for SST remotely sensed from satellites to be launched in future.

• Journal of the Korean association of regional geographers
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• 제4권2호
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• pp.151-164
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• 1998

I analyzed the correlation between El-Nino phenomenon and our country's temperature and precipitation laying the stress on the anomaly, and the result of this analysis is as follows: (1) The extraction of the occurrences of El-Nino at the place of sea surface around Nino.3 which was known as the sea area under observation for El-Nino reveals that there are 9 years (1969, 1970, 1973, 1977, 1987, 1992, 1995, 1998) when the temperature anomaly in January is more than 1.0 during the period of research years ($1969{\sim}1998$). (2) The tendency of change of sea surface temperature around Nino.3 and that of our country are about the same, but the anomaly of Pusan and Inchon was much greater than that of Jangki in the East Coast. (3) The anomaly of sea surface temperature around Nino.3 and that of the ground temperature showed the similar changing tendency, the temperature of our country has something to do with that of sea surface as the correlation of ground temperature with the temperature of sea surface showed 0.31. Anomaly warm winter has something to do with El-Nino because the temperature of our country was high when El-Nino phenomenon appeared. (4) As for the precipitation, we can see that it has generally increased after 1989 when the phenomenon of warm climate was intense than before that year. But as we study the change of anomaly, the precipitation has less correlation in comparison with the ground temperature. The precipitation in 1973, 1983 and 1987 which were El-Nino years was correlated with El-Nino. While the change of sea surface temperature has showed a tendency of plus(+)increase since 1990, the precipitation has showed a tendency of minus (-)decrease. Therefore it seems that the temperature of sea surface has little correlation with the amount of rainfall.

• Korean Journal of Remote Sensing
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• 제38권3호
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• pp.265-282
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• 2022

Sea surface temperature (SST) is a factor that greatly influences ocean circulation and ecosystems in the Earth system. As global warming causes changes in the SST near the Korean Peninsula, abnormal water temperature phenomena (high water temperature, low water temperature) occurs, causing continuous damage to the marine ecosystem and the fishery industry. Therefore, this study proposes a methodology to predict the SST near the Korean Peninsula and prevent damage by predicting abnormal water temperature phenomena. The study area was set near the Korean Peninsula, and ERA5 data from the European Center for Medium-Range Weather Forecasts (ECMWF) was used to utilize SST data at the same time period. As a research method, Long Short-Term Memory (LSTM) algorithm specialized for time series data prediction among deep learning models was used in consideration of the time series characteristics of SST data. The prediction model predicts the SST near the Korean Peninsula after 1- to 7-days and predicts the high water temperature or low water temperature phenomenon. To evaluate the accuracy of SST prediction, Coefficient of determination (R²), Root Mean Squared Error (RMSE), and Mean Absolute Percentage Error (MAPE) indicators were used. The summer (JAS) 1-day prediction result of the prediction model, R²=0.996, RMSE=0.119℃, MAPE=0.352% and the winter (JFM) 1-day prediction result is R²=0.999, RMSE=0.063℃, MAPE=0.646%. Using the predicted SST, the accuracy of abnormal sea surface temperature prediction was evaluated with an F1 Score (F1 Score=0.98 for high water temperature prediction in summer (2021/08/05), F1 Score=1.0 for low water temperature prediction in winter (2021/02/19)). As the prediction period increased, the prediction model showed a tendency to underestimate the SST, which also reduced the accuracy of the abnormal water temperature prediction. Therefore, it is judged that it is necessary to analyze the cause of underestimation of the predictive model in the future and study to improve the prediction accuracy.

• Journal of the Korean Geophysical Society
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• 제4권1호
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• pp.71-84
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• 2001

A study was initiated to investigate whether the groundwaters being discharged into the sea could be used as a possible water resources. This paper presents a preliminary information about the groundwaters being discharged along the shoreline of East Sea. Major discharge sites were selected primarily on the basis of the informaion on surface temperatures of the sea. Hydrogeologic and geographic conditions were also considered in selecting the major discharge sites. The development possibility of the discharging groundwater were estimated roughly, considering populations, industries and social development compatibilities of the selected areas. Groundwater dams and linked usage with surface water were suggested as possible development methods for the groundwaters.. Based on this study, we selected about 60 sites as the major discharge areas and tentatively recommended 6 sites as optimal sites for development of groundwaters being discharged into the sea. However, detailed in-situ hydrogeologic surveys are required prior to the final decision.

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1094-1100
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• 2014

TEvaporator is key component in food, seawater distillation and waste water treatment system, which is basically to concentrate the raw liquid by evaporating the pure water under vacuum condition. The liquid concentration is performed through the membrane, electro-dialysis and evaporation. In this study, only the evaporating type was treated for evaluating the economic analysis with the various operating conditions. The results of this study showed that the performance of the OT-MSF desalination system is increased with decreasing the temperature difference between the neighboring evaporators, which means that the number of evaporators is increased, under the determined design conditions.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 한국표면공학회 2015년도 추계학술대회 논문집
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• pp.321-321
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• 2015

해수 환경에 노출된 대부분의 금속재료는 직 간접적으로 부식의 영향을 받는다. 이와 같이 해수에 침지된 금속재료의 부식 방지에는 음극방식법이 주로 사용되고 있다. 과거의 음극방식 설계에는 양극 크기와 방식전류 밀도, 소모율 등 양극 자체에 대한 변수만이 고려되었으나, 20여 년 전부터는 해수 오염도, 수온 및 유속 등을 종합적으로 고려하여 설계하고 있다. 특히 대부분의 금속은 부식성 환경에서 생성된 부동태 피막이 해수 유동에 의해 파괴되면서 급속히 손상된다. 따라서 본 연구에서는 해수 특성을 고려한 최적의 소요방식전류밀도 선정을 위해 전기화학실험을 실시하였다. 실험 결과, 해수 온도 상승에 따라 확산속도가 빨라져 최적 방식 전류밀도가 증가하는 경향을 나타냈다.

• Journal of Advanced Marine Engineering and Technology
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• 제35권4호
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• pp.373-378
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• 2011

The freeze desalination cycle with seawater heat pump system is simulated and designed for the basic data for the design of freeze desalination system. The basic model of seawater heat pump system is refrigeration cycle and indirect freeze desalination method is used for seawater desalination. The cycle performance of seawater heat pump such as COP, compressor work, condensing capacity was analyzed and the desalination performance such as fresh water productivity and energy per unit fresh water productivity was compared with respect to the seawater temperature of condenser inlet and ice ratio in the evaporator. The compressor work and condensing capacity decreased with respect to the decrease of seawater inlet temperature. The energy per unit fresh water productivity in case of $8^{\circ}C$ seawater inlet temperature showed 28.9% lower than that of $20^{\circ}C$.

• Journal of the Korean Institute of Gas
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• 제23권1호
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• pp.41-46
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• 2019

LNG is supplying to consumers as gas phase vaporized by major seawater vaporizer, i.e.. open rack vaporizers. But as soon as the temperature of seawater drops below $5^{\circ}C$ in winter, the submerged evaporators should be operated and cause a lot of energy consumption because of their natural gas combustion. In order to reduce the consumption amount, in this study new two-way supplying method of seawater instead of the present one-way supplying system is introduced and analysed the technical possibilities and economical savings. The results showed that in case of the temperature of seawater becomes below $2.5^{\circ}C$, LNG can be evaporated using ORV without operating S MV. If this system is applied in Incheon LNG terminal, the energy saving reaches 11,770 Ton of LNG as 11,760 million won. By the analysis, the two-way supplying system of seawater in ORV can be the most effective method to be able to save huge amount of energy every year.

• Proceedings of KOSOMES biannual meeting
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• 해양환경안전학회 2017년도 공동학술발표회
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• pp.229-229
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• 2017

• Journal of the Korean earth science society
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• 제27권1호
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• pp.61-72
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• 2006

Numerical studies on the influence of interaction between atmosphere and ocean on the variation of Karman vortex at the lee side of Jeju Island were carried out. Karman vortex tends to be occurred at limited height associated with Hanla mountain. And we can find clear Karman vortex at 900 hPa height in this study. One big vortex cell occurred at lee side of Jeju Island in the begging stage of its development and the cell was divided into three small cells as time goes by. And the strength and lifetime of small vortexes depend on the distribution of SST (Sea Surface Temperature). Weak gradient of SST makes long-lasting Karman vortex but produces weak potential vorticity at lee side of Jeju-do in comparison with the vortex under strong SST gradient. Strong SST gradient also increases not only the mixing depth but also the mixing ratio at lower level of troposphere. And the increased atmospheric mixing decreases the mechanical forcing due to isolated topography. Then the strength of Karman vortex at the lee side of Jeju Island becomes weak under strong gradient of SST. Thus the evolution of Karman vortex is closely related to distribution of SST around the isolated island.