• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.323-324
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• 2022

This paper explains the comparison results of surface current measurement using X-band Radar image through analysis. Measurements were carried out from February 2022 using the X-band Radar for marin ships installed at Sokcho Beach. Based on the Korea Hydrographic and Oceanographic Agency ocean observation buoys, the accuracy of surface current(current speed) measurement was verified through comparison and analysis of measurement data.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.172-175
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• 2003

This paper deals with the network interface of research and observation instruments in the oceanographic research vessel with an establishment of related database for measured information. The system is implemented to integrated communication network system which allows to effective survey by using real time observation and GUI(Graphic User Interface). The system also consists of the LAN systems and serial interface to link chemical, physical, biological and environmental relations. And, other network service and vessel data service for data communication between vessel and earth station such as INMARSAT-B, WWW service, BBS, E-Mail etc. are needed for integrated communication network system.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.3
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• pp.103-117
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• 2017

This note provides technical guide on three issues associated with establishing and automatically running regional ocean forecasting systems: (1) a strategy for continuous production of hourly-interval three-day ocean forecast data, (2) the daily download of ocean and atmospheric forecasting data (i.e., HYCOM and NOAA/NCEP GFS data), which are provided by outside institutions and used as initial condition, surface forcing, and boundary data for regional ocean models, and (3) error notifications to numerical model managers through the Short Message Service (SMS). Guidance on dealing with these three issues is illustrated via solutions implemented by the Korea Hydrographic and Oceanographic Agency, since in embarking on this project we found that this procedural information was not readily available elsewhere. This technical guide is based on our experiences and lessons learned during the process of establishing and operating regional ocean forecasting systems for the East Sea and the Yellow and East China Seas over the 5 year period of 2012-2016. The fundamental approach and techniques outlined in this guide are of use to anyone wanting to establish an automatic regional and coastal ocean forecasting system.

• Journal of the Korean earth science society
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• v.42 no.5
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• pp.524-535
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• 2021

Rapid climate change and oceanic warming have increased the variability of oceanic wave heights over the past several decades. In addition, the extreme wave heights, such as the upper 1% (or 5%) wave heights, have increased more than the heights of the normal waves. This is true for waves both in global oceans as well as in local seas. Satellite altimeters have consistently observed significant wave heights (SWHs) since 1991, and sufficient SWH data have been accumulated to investigate 100-year return period SWH values based on statistical approaches. Satellite altimeter data were used to estimate the extreme SWHs at the Ieodo Ocean Research Station (IORS) for the period from 2005 to 2016. Two representative extreme value analysis (EVA) methods, the Initial Distribution Method (IDM) and Peak over Threshold (PoT) analysis, were applied for SWH measurements from satellite altimeter data and compared with the in situ measurements observed at the IORS. The 100-year return period SWH values estimated by IDM and PoT analysis using IORS measurements were 8.17 and 14.11 m, respectively, and those using satellite altimeter data were 9.21 and 16.49 m, respectively. When compared with the maximum value, the IDM method tended to underestimate the extreme SWH. This result suggests that the extreme SWHs could be reasonably estimated by the PoT method better than by the IDM method. The superiority of the PoT method was supported by the results of the in situ measurements at the IORS, which is affected by typhoons with extreme SWH events. It was also confirmed that the stability of the extreme SWH estimated using the PoT method may decline with a decrease in the quantity of the altimeter data used. Furthermore, this study discusses potential limitations in estimating extreme SWHs using satellite altimeter data, and emphasizes the importance of SWH measurements from the IORS as reference data in the East China Sea to verify satellite altimeter data.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.89-91
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• 2014

전자해도는 IHO의 S-57 ENC Product Specification에 따라 해양의 모든 지형정보를 포함하는데, 해양의 지형정보에는 해안선, 등심선, 수심 그리고 항로표지 등이 포함된다. 전자해도가 포함하는 정보는 수로측량을 통해 제작된 측량원도를 이용하여 제작하는데, 대용량의 측량원도 자료는 매우 조밀하고 양이 방대하여 전자해도에 반영하기 위해서는 수심 정보를 발췌하여야 한다. 국립해양조사원에서는 측량원도의 정보를 발췌하기 위한 방안으로 수심편수규칙을 정하고 있으며, 편수 단계와 편수 후 검증 단계를 거쳐 전자해도의 수심 정보를 제작하고 있다. 그러나 편수와 편수 후 검증은 모두 수작업으로 진행하고 있어, 보다 효율적이고 정확한 방법으로 수심 편수 결과를 검증하기 위한 방안이 필요하다. 본 논문에서는 수심 편수 결과를 규칙에 맞도록 편수되었는지를 평가하는 방안을 연구하였다. 각 편수된 수심을 들로네 삼각분할 기법에 따라 영역을 삼각분할하고, 측량원도의 수심 정보와 삼각분할 된 삼각형과 비교 분석하여 수심이 수심편수규칙을 준수하는지를 비교분석하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.299-300
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• 2022

4차 산업혁명으로 자율화·지능화됨에 따라 육·해상의 교통수단에 ICT 기술을 활용한 자율운행차 자율운항선박 등 신기술 및 서비스 개발이 점차 확대되고 있다. 본 연구에서는 해상분야의 자율운항선박 자율주행에 필요한 기술 도출을 위한 방법으로 육상분야의 자율주행차량의 핵심기술인 센서기술과 AI기술에 대해 알아보고 비교 분석하고자 한다. 자율주행차 주행을 위한 기술개발은 센서와 정밀도로정보(지도) 2트랙으로 개발이 진행되고 있으나, 최근 센서 오류 등으로 인한 사고발생이 잦아 정밀도로정보(지도) 중요성이 증가하고 있어 정밀도로 정보 구축을 서두르고 있다. 반면 자율운항선박의 경우 충돌회피 기술, 최적항로 개발, 정보보안 등 기술개발이 이루어지고 있으나 AI용 수로정보에 한 대비는 진행되고 있지 않고 있다. 따라서, 자율운항선박의 안전한 자율주행을 위한 방법으로 AI 알고리즘 연산과정에서 기계적으로 이용 가능하고 목적에 적합한 수로정보 구축이 필요하며 우리나라 선박의 안전운항을 위해 국가차원에서 수로정보 수집 및 생산을 담당해야 하므로 국가에서 주도하에 연구개발이 진행되어야 할 것이다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.2
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• pp.37-48
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• 2006

HF radar-derived current data obtained in 2002 and 2004 are analyzed to examine the effects of the completion of the Saemangeum 4th tidal dyke in June 2003, connecting Gogunsan-Gundo and Bieung-Do, on the coastal surface $M_2$ current pattern. Comparison between the currents by HF radar and current meter mooring showed good agreements. Counterclockwise rotation of the $M_2$ current in the observed area did not change with the dyke construction. Strong westward ebb jet from the gap of the dyke was observed in 2002 but disappeared in 2004. The complete closing of the dyke gap caused the current speed increase around the mouth of the Kem River estuary, decrease around Gogunsan-Gundo and the dyke, the changes in the direction of maximum current to north-ward from eastward and the delay of the maximum flood current occurrence around Gogunsan-Gundo and the dyke. Around Yeon-Do, the maximum flood current directed more clockwise and occurred rather earlier. These changes of the $M_2$ current ellipse characteristics imply that the effects of the dyke construction reached the area connecting Mal-Do and Yeun-Do.

• Journal of the Korean earth science society
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• v.43 no.5
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• pp.591-603
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• 2022

The color and optical properties of seawater are determined by the interaction between dissolved organic and inorganic substances and plankton contained in it. The Ieodo - Ocean Research Institute (I-ORS), located in the East China Sea, is affected by the low salinity of the Yangtze River in the west and the Tsushima Warm Current in the south. Thus, it is a suitable site for analyzing the fluctuations in circulation and optical properties around the Korean Peninsula. In this study, seawater surrounding the I-ORS was classified according to its optical characteristics using the satellite remote reflectance observed with Moderate Resolution Imaging Spectroradiometer (MODIS)/Aqua and National Aeronautics and Space Administration (NASA) bio-Optical Marine Algorithm Dataset (NOMAD) from January 2016 to December 2020. Additionally, the variation characteristics of optical water types (OWTs) from different seasons were presented. A total of 59,532 satellite match-up data (d ≤ 10 km) collected from seawater surrounding the I-ORS were classified into 23 types using the spectral angle mapper. The OWTs appearing in relatively clear waters surrounding the I-ORS were observed to be greater than 50% of the total. The maximum OWTs frequency in summer and winter was opposite according to season. In particular, the OWTs corresponding to optically clear seawater were primarily present in the summer. However, the same OWTs were lower than overall 1% rate in winter. Considering the OWTs fluctuations in the East China Sea, the I-ORS is inferred to be located in the transition zone of seawater. This study contributes in understanding the optical characteristics of seawater and improving the accuracy of satellite ocean color variables.

• Journal of the Korean earth science society
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• v.44 no.1
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• pp.13-35
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• 2023

Ocean currents play the most important role in causing and controlling global climate change. The water depth of the Yellow Sea is very shallow compared to the East Sea, and the circulation and currents of seawater are quite complicated owing to the influence of various wind fields, ocean currents, and river discharge with low-salinity seawater. The Yellow Sea Warm Current (YSWC) is one of the most representative currents of the Yellow Sea in winter and is closely related to the weather of the southwest coast of the Korean Peninsula, so it needs to be treated as important in secondary-school textbooks. Based on the 2015 revised national educational curriculum, secondary-school science and earth science textbooks were analyzed for content related to the YSWC. In addition, a questionnaire survey of secondary-school science teachers was conducted to investigate their perceptions of the temporal variability of ocean currents. Most teachers appeared to have the incorrect knowledge that the YSWC moves north all year round to the west coast of the Korean Peninsula and is strong in the summer like a general warm current. The YSWC does not have strong seasonal variability in current strength, unlike the North Korean Cold Current (NKCC), but does not exist all year round and appears only in winter. These errors in teachers' subject knowledge had a background similar to why they had a misconception that the NKCC was strong in winter. Therefore, errors in textbook contents on the YSWC were analyzed and presented. In addition, to develop students' and teachers' data literacy, class materials on the YSWC that can be used in inquiry activities were developed. A graphical user interface (GUI) program that can visualize the sea surface temperature of the Yellow Sea was introduced, and a program displaying the spatial distribution of water temperature and salinity was developed using World Ocean Atlas (WOA) 2018 oceanic in-situ measurements of water temperature and salinity data and ocean numerical model reanalysis field data. This data visualization materials using oceanic data is expected to improve teachers' misunderstandings and serve as an opportunity to cultivate both students and teachers' ocean and data literacy.

• 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.