• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.307-308
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• 2006

The national goal of wind energy dissemination has to be determined rationally based on technically available wind resource potential. For a reliable and scientific estimation or wind resource potential, a wind map is requisite. This paper presents the national wind map of Korea established by numerical wind simulation. Prediction accuracy of the low-resolution wind map is Improved by nudging QuikSCAT data and is validated by comparing with marine buoy beacon and met-mast measurements. Therefore, quantification of national wind resource potential is now possible and is anticipating to be utilized as a core index for policy and strategy building of wind energy dissemination and technology development.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.518-524
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• 2008

A three-dimensional primitive equation model (POM) and the buoy data (2900 N, 13500 E) from the Japan Meteorological Agency (JMA) for 27 typhoons between 1982 and 2000 are used to investigate the sea surface cooling (SSC) that accompanies typhoons in the northwestern Pacific. Observed sea surface temperatures (SSTs) rapidly drop 0.6 to 4.3 C, and SSC continues for several weeks after the passage of a typhoon. The model, which covers most of the northwestern Pacific ($24^{\circ}N$ to $52^{\circ}N$), simulated Typhoon Abby over the tropical Pacific, and successfully reproduces many observed features, including the pattern of SST decrease, inertial oscillations, etc. The model accurately simulated the SSC process, suggesting that the cyclonic eddy with a radius of a few hundred kilometers that trailed Typhoon Abby plays an important role in SSC.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.813-825
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• 2014

To maximize electric power production using wave energy extractions from resonance power buoys, the maximum motion displacement spectra of the buoys can primarily be obtained under a given wave condition. In this study, wave spectra observed in shoaling water were formulated. Target resonance frequencies were established from the arithmetic means of modal frequency bands and the peak frequencies. The motion characteristics of the circular cylindrical power buoys with corresponding drafts were then calculated using numerical models without considering PTO damping force. Results showed that the heave motions of the power buoys in shoaling waters with insufficient drafts produced greater amplification effects than those in deep seas with sufficient drafts.

• Journal of Navigation and Port Research
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• v.33 no.7
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• pp.501-504
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• 2009

There are many difficulties to supply constant power to marine facilities which operate in the sea. Especially, there is a limit to stand alone power supply systems due to the influence of weather conditions. That's why a hybrid power supply system is required to overcome these problems. This paper will describe an Electronic Anti-Fouling System (EAFS) to maximise the power efficiency for a solar - wave hybrid power generation system. A main factor reducing the efficiency of a Wave Energy Converter (WEC) is due to the attachment of aquatic life forms. Therefore the aim of this research is to develop a simulation programme to enable the design of more efficient EAFS for hybrid power generation systems and to provide valuable data for production of more efficient EAFS.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.5
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• pp.316-325
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• 2010

Harmonic analyses are carried out in order to obtain the major frequency components of the air temperature (AT) and surface water temperature (SWT) data monitored in the Middle Area of the Yellow Sea (Yellow Sea monitoring buoy). The analysis shows the annual and semi-annual components are predominant and the higher frequency components are relatively weak with contribution to the short fluctuations, i.e. below $0.2{\sim}0.5^{\circ}C$, in the AT and SWT. The standard deviation of the AT residual is 2.4 times larger than that of the SWT residual and the occurrence frequency distributions of the AT and SWT residual components are both closely fitted to a normal-distribution function. The variation pattern on the AT-SWT plane forms the clear continuous hysteresis loop in anti-clockwise direction which is composed of the AT-SWT rising period, AT-SWT falling period, and the constant SWT period in winter season.

• Journal of the Korean earth science society
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• v.39 no.6
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• pp.555-567
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• 2018

In order to identify the characteristics of sea surface temperature (SST) differences between microwave SST from GCOM-W1/AMSR2 and in-situ measurements in the western coast of Korea, a total of 6,457 collocated matchup data were produced using the in-situ temperature measurements from marine buoy stations (Deokjeokdo, Chilbaldo, and Oeyeondo) from July 2012 to December 2017. The accuracy of satellite microwave SSTs was presented by comparing the ocean buoy data of Deokjeokdo, Chilbaldo, and Oeyeondo stations with the AMSR2 SST data more than five years. The SST differences between the microwave SST and the in-situ temperature measurements showed some dependence on environmental factors, such as wind speed and water temperature. The AMSR2 SSTs were tended to be higher than the in-situ temperature measurements during the daytime when the wind speed was low ($<6ms^{-1}$). On the other hand, they showed positive deviation increasingly as the wind speed increased for nighttime. In addition, increasing tendency of SST differences was related to decreasing sensitivity of microwave sensors at low temperatures and data contamination by land. A monthly analysis of the SST difference showed that unlike the previous trend, which was known to be the largest in winter when strong winds were blowing, the SST difference was largest in summer in Deokjeokdo and Chilbaldo buoy stations. This seemed to be induced by differential tidal mixing at the collocated matchup points. This study presented problems and limitations of the use of microwave SSTs with high contribution to the SST composites in the western coastal region off the Korean peninsula.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.3
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• pp.142-149
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• 2005

To provide observed oceanography data at coastal fish and shellfish farm in the northeastern sea of the Korean peninsula on real time base, we developed real time application system for fisheries oceanography information. The system has been made up a mooring buoy system, a server for oceanography data collection, a server for archiving data and a database system, and a web server for providing fisheries oceanography information using internet. Futhermore, to support letters service on a cellular phone, we developed the communication system from mooring buoy to cell phone on real time base. The oceanography data derived from the system are water temperature speed and direction of current in surface layer middle layer and bottom layer in hour. We were able to quantify short term variation of ocean conditions within several days at shellfish farm such as a scallop sea farm using our system. To reduce damages of fish and shellfish farm from abnormal phenomena of ocean conditions such as a broken stratification of water, an occurrence of abnormal coastal cold water and warm water we will be able to move vertically and horizontally the sea farm facilities to proper conditions using real time oceanography information derive from the system.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.120-128
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• 2016

This paper describes power generation from sea waves by using linear permanent magnet generator. A buoy is placed on the ocean surface and connected to the generator. The wave energy is carried out from the movement of a buoy. An electrical conversion system is needed between the generator and the grid. For an analysis of the power system, the modeling of the linear generator and converter system was proceeded. This paper proposes vector control method for wave power generation system using linear generator. In order to verify the proposed method, simulation and experiment performed and the results support the validity of the control scheme.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.869-875
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• 2016

The purpose of this study is to analyze the long-term wave characteristics and tendencies of coastal waters near Korea based on wave hind-casting modelling. Wave hind-casting modelling was performed with a wind data set from ECMWF (2001~2014), which provides data from 1979 to the present. The results of numerical modelling were verified with observed data collected using wave buoys installed by the Korea Meteorological Administration (KMA) and Korea Hydrographic and Oceanographic Agency (KHOA) in offshore waters. The results agreed well with observations from buoy stations, especially during event periods such as typhoons. The quantitative RMSE value was 0.5 m, which was significant. Consequently, the results of a wave tendency analysis for 14 years (2001~2014) showed an increased appearance ratio for waves of more than 2 m in height at all regional domains. The mean appearance ratio was 0.082 % per year, which implies that coastal waves have been increasing continuously. This coastal wave tendency analysis data can be used to evaluate coastal vulnerability due to recent climate change and the design of coastal erosion prevention structures.

• Ocean and Polar Research
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• v.30 no.3
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• pp.361-372
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• 2008

A satellite tracked drifter experiment was conducted to observe thermal structure and surface circulation in the northeastern East China Sea. For this experiment, four ADOS buoys, assembled with surface float and thermister chain, were deployed on August 2007 in southern Jeju-do, where the Kuroshio Branch Current is separated from the main stream. Thermal structure in the upper layer of the northeastern East China Sea was successfully observed during the following $1{\sim}3$ months. Strong thermo-haline front in a northeast-southwest direction was observed. In the frontal zone, warm and saline Kuroshio origin water intermixes with fresher coastal water and flows toward the Korean Strait. Typhoon Nari, which passed over the East China Sea 20 days after commencement of study, caused distinct signals in the thermal structure and trajectory of buoys. During the typhoon, surface temperature abruptly dropped to about $4^{\circ}C$, while the thermocline formed at $30{\sim}50$ m depth vanished due to strong vertical mixing. Internal inertial oscillation occurred several days after the typhoon. The fortuitous occurrence of typhoon Nari showed that ADOS buoys can provide useful and accurate air-sea interaction data during typhoons.