• Korean Journal of Remote Sensing
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• v.14 no.3
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• pp.223-231
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• 1998

Ocean Scanning Multispectral Imager (OSMI) is a payload on the Korean Multi-Purpose SATellite (KOMPSAT) to perform worldwide ocean color monitoring for the study of biological oceanography. The instrument images the ocean surface using a whisk-broom motion with a swath width of 800 km and a ground sample distance (GSD) of less than 1 km over the entire field-of-view (FOV). The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/offset and on-orbit image data storage. The instrument also performs sun calibration and dark calibration for on-orbit instalment calibration. The OSMI instrument is a multi-spectral imager covering the spectral range from 400 nm to 900 nm using a Charge Coupled Device (CCD) Focal Plane Array (FPA). The ocean colors are monitored using 6 spectral channels that can be selected via ground commands after launch. The instrument performances are fully measured for 8 basic spectral bands centered at 412, 443, 490, 510, 555, 670, 765 and 865 nm during ground characterization of instalment. In addition to the ground calibration, the on-orbit calibration will also be used for the on-orbit band selection. The on-orbit band selection capability can provide great flexibility in ocean color monitoring.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1111-1124
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• 2021

Mudflats are crucial for understanding the ecological structure and biological function of coastal ecosystem because of its high primary production by microalgae. There have been many studies on measuring primary productivity of tidal flats for the estimation of organic carbon abundance, but it is relatively recent that optical remote sensing technique, particularly hyperspectral sensing, was used for it. This study investigates hyperspectral sensing of chlorophyll concentration on a tidal flat surface, which is a key variable in deriving primary productivity. The study site is a mudflat in Geunso bay, South Korea and field campaigns were conducted at ebb tide in April and June 2021. Hyperspectral reflectance of the mudflat surfaces was measured with two types of hyperspectral sensors; TriOS RAMSES (directionalsensor) and the Specim-IQ (camera sensor), and Normal Differenced Vegetation Index (NDVI) and Contiuum Removal Depth (CRD) were used to estimate Chl-a from the optical measurements. The validation performed against independent field measurements of Chl-a showed that both CRD and NDVI can retrieve surface Chl-a with R² around 0.7 for the Chl-a range of 0~150 mg/m² tested in this study.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.1
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• pp.36-46
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• 2013

The Geostationary Ocean Color Imager (GOCI), the first geostationary ocean color observation instrument launched in 2010 on board the Communication, Ocean, and Meteorological Satellite (COMS), has been generating the operational level 1 data. This study describes a methodology for creating the GOCI true color image and data processing software, namely the GOCI RGB maker. The algorithm uses a generic atmospheric correction and reprojection technique to produce the color composite image. Especially, the program is designed for educational purpose in a way that the region of interest and image size can be determined by the user. By distributing software to public, it would maximize the understanding and utilizing the GOCI data. Moreover, images produced from the geostationary observations are expected to be an excellent tool for monitoring environmental changes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.18-24
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• 1999

The satellite image acquired by RADARSAT SAR on August 15, 1996 reveals internal waves in north coastal waters of Cheju Island. It is indicated from the image data, the tidal elevation data, and the bottom topography data, the internal waves seem to be generated by interaction between shallow bottom and tidal currents travelling in the stratified water in the summer time during the tidal changeovers from ebb to flood. The internal waves generated in such condition show patterns of trains of solitons. Probable amplitude of observed solitons is calculated using estimation of the soliton wave length from SAR image data and K-dV equation. Detection of the internal waves is very significant not only to military strategist for underwater maneuvers such as operation of submarines, but also to physical and biological oceanographers. Temporal and spatial variation of the internal waves are needed to be measured by simultaneous in-situ field study together with SAR to examine the nature of these internal waves.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.3
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• pp.189-197
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• 2006

The influence of leodo Ocean Research Station structure to surrounding atmospheric flow is carefully investigated using CFD techniques. Moreover, the validation works of computational results are performed by the comparison with the observed data of leodo Ocean Research station. In this paper, we performed 3-dimensional CAD modelling of the station, generated the grid system for numerical analysis and carried out flow analyses using Navier-Stokes equations coupled with two-equation turbulence model. For suitable free stream conditions of wind speed and direction, the interference of the research station structure on the flow field is predicted. Beside, the computational results are benchmarked by observed data to confirm the accuracy of measured date and reliable data range of each measuring position according to the wind direction. Through the results of this research, now the quantitative evaluation of the error range of interfered gauge data is possible, which is expected to be applied to provide base data of accurate sea surface wind around research stations.

• Korean Journal of Remote Sensing
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• v.24 no.6
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• pp.559-569
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• 2008

The Geostationary Ocean Color Imager (GOCI) on board the Communication Ocean Meteorological Satellite (COMS), the first geostationary ocean color sensor, requires accurate atmospheric correction since its eight bands are also affected by atmospheric constituents such as gases, molecules and atmospheric aerosols. Unlike gases and molecules in the atmosphere, aerosols can interact with sunlight by complex scattering and absorption properties. For the purpose of qualified ocean remote sensing, understanding of aerosol-radiation interactions is needed. In this study, we show micro-physical and optical properties of aerosols using the Optical Property of Aerosol and Cloud (OPAC) aerosol models. Aerosol optical properties, then, were used to analysis the relationship between theoretical satellite measured radiation from radiative transfer calculations and aerosol optical thickness (AOT) under various environments (aerosol type and loadings). It is found that the choice of aerosol type makes little different in AOT retrieval for AOT<0.2. Otherwise AOT differences between true and retrieved increase as AOT increases. Furthermore, the differences between the AOT and angstrom exponent from standard algorithms and this study, and the comparison with ground based sunphotometer observations are investigated. Over the northeast Asian region, these comparisons suggest that spatially averaged mean AOT retrieved from this study is much better than from standard ocean color algorithm. Finally, these results will be useful for aerosol retrieval or atmospheric correction of COMS/GOCI data processing.

• 한국지구과학회:학술대회논문집
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• 2010.04a
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• pp.133-133
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• 2010

인공위성 SAR센서는 기존 산란계 해상풍 자료의 낮은 해상도로 인한 여러 한계를 극복함으로써 다양한 해양연구에 있어 필요성과 활용영역이 넓어지고 있다. 이러한 추세에 따라 전세계적으로 다파장 SAR 센서들이 운용 또는 발사 예정에 있음에도 불구하고 현재까지 한반도 주변해에 대한 SAR 해상풍 산출 연구는 C밴드에만 한정되어왔다. 본 연구에서는 L밴드 해상풍 추출알고리즘을 적용하여 L밴드 SAR 영상으로부터 한반도 주변해의 해상풍을 추출하고 산란계 해상풍 자료와 비교 분석을 통해 정확도 특성을 제시하고자 하였다. 2007년 8월 우리나라 동해 지역을 관측한 L밴드 ALOS PALSAR 영상에 대해 L밴드 HH편광 GMF 알고리즘을 적용하여 해상풍을 산출하였다. 산출 해상풍은 동일시점의 산란계 QuikSCAT 자료와 공간적으로 유사한 패턴을 보였으며 두 자료 간의 풍속오차는 3.45m/s로 나타났다. 연구 해역과 같이 강한 바람 범위에서는 산출 해상풍 간의 차이가 크게 나타나며 풍향으로 인한 오차특성이 보인다. 특히 풍속의 경우, 산란계 해상풍이 중간바람 범위에 집중된 것에 비해 L밴드 SAR 산출 해상풍은 강한 바람 범위까지 포함하는 넓은 풍속값 범위를 나타냈다.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.135-141
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• 2009

A preliminary thermal analysis is performed for the optical payload system of a geostationary satellite. The optical payload considered in this paper is GOCI(Geostationary Ocean Color Imager) of COMS of Korea. The radiative and conductive thermal models are employed in order to predict thermal responses of the GOCI on the geostationary orbit. According to the results of this analysis are as follows: 1) the GOCI instrument thermal control is satisfactory to provide the temperatures for the GOCI performances, 2) the thermal control is defined and interfaces are validated, and 3) the entrance baffle temperature is found slightly out its specification, therefore further detailed analyses should be continued on this element.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.49-49
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• 2003

2008년 발사 예정인 통신해양기상위성(Communication, Ocean and Meteorological Satellite)의 성공적인 임무완성에 기여하기 위해 본 연구에서는 해양위성 관측자료 분석에 적용할, 위성의 위치 및 하루 또는 연중 태양의 위치에 따른 해수면 태양반사(Sunglint) 영역의 정확한 위치를 찾아주는 예측 알고리즘을 연구하였다. 정지궤도위성의 태양반사 영역의 정확한 위치 결정은 태양-위성-지구를 고려한 구면 천문학과 반사의 법칙으로부터 계산할 수 있는데 적절한 구면 좌표계에서 하루 또는 연중 태양의 위치와 위성의 위치를 통해 얻어진 비선형 방정식을 Newton-Raphson 수치 방법을 이용하여 태양반사 영역의 정확한 위치와 움직임을 계산하였다. 또한 정지궤도위성이 아닌 극궤도위성의 태양반사 영역의 위치 결정은 해당 위성의 TLE(Two Line Elements)을 이용한 궤도분석 프로그램인 ASAP(Artificial Satellite Analysis Program)을 이용해 시간에 따른 위성의 위치를 구하여 정지궤도위성에서의 위치 결정 알고리즘과 같은 방식으로 연구를 수행하였다. 본 논문에서 연구한 기본적인 알고리즘을 통해 다양한 이미지 센서를 가진 궤도 위성에서의 태양반사 영역 위치 결정과 그와 관련된 연구를 수행 할 수 있을 것으로 기대한다.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.119-125
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• 2006

The first GEO satellite, COMS(Communication. Ocean & Meteorological Satellite) developed by Korean participants is a multi-functional satellite accommodating two observation payloads and a communication payload. Because of the inherent requirements given by these payloads, the physical layout of the instruments and sensors and of their electronics packages is critical to mission success. This technical paper presents an overview of the mechanical system design during the preliminary design phase and describes the design consideration to achieve the optimized performance.