• 한국지구과학회지
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• 제24권1호
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• pp.7-21
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• 2003

The state-of-art third generation wave prediction model WAM was applied to the Korean seas for a winter monsoon period of January 1997. The wind field used in the present study is the global NSCAT-ERS/NCEP blended winds, which was further interpolated using a bi-cubic spline interpolator to fine grid limited area shallow water regime surrounding the Korean seas. To evaluate and investigate the accuracy of WAM, the hindcasted wave heights are compared with observed data from two shallow water buoys off Chil-Bal and Duk-Juk. A detailed study has been carried with the various meteorological parameters in observed buoy data and its inter-dependency on model computed wave fields was also investigated. The RMS error between the observation and model computed wave heights results to 0.489 for Chil-Bal and 0.417 for Duk-Juk. A similar comparison between the observation and interpolated winds off Duk-Juk show RMS error of 2.28 which suggest a good estimate for wave modelling studies.

• 항공우주산업기술동향
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• 제9권1호
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• pp.45-54
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• 2011

최근 전 세계 다양한 지구관측 위성이 개발 및 발사됨에 따라 다양한 분야로 위성영상 자료의 활용이 확대되고 그에 따른 지구관측 위성영상 시장의 규모가 점점 커지고 있는 추세이다. 일본의 경우 빈번하게 발생하는 재해재난 분야에 대응하고, 실질적으로 피해복구 지원에 ALOS 위성자료를 적극적으로 활용하고 있으며, 전 세계 재해재난 저감 활동에 자국이 보유한 위성자료를 지원하여 국제사회에 기여하는 바가 크다고 할 수 있다. 본 논문을 통하여 일본의 원격탐사 활용 실태와 관련 정책 동향을 살펴보고자 한다. 또한, 위성기반의 원격탐사 기술이 국민 실생활에 어떻게 효율적으로 기여할 수 있을 지에 대한 방안과 관련 지원을 위해 요구되는기반시스템의구축에대해서조사하였다.

• Ocean and Polar Research
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• 제23권2호
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• pp.141-160
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• 2001

The challenge of predicting the Japanese coastal ocean motivated Frontier Observational Research System for Global Change (FORSGC) and the Japan Marine Science and Technology Center (JAMSTEC) to start a multiyear observational programme in the upstream Kuroshio in November 2000. This field effort, the Kuroshio Observation Program (KOP), should enable us to determine the barotropic and baroclinic components of the western boundary current system, thus, to better understand interactions of the currents with mesoscale eddies, the Kuroshio instabilities, and path bimodality. We, then, will be able to improve modeling predictability of the mesoscale, seasonal, and inter-annual processes in the midstream Kuroshio near the Japanese main islands by using this knowledge. The KOP is focused on an enhanced regional coverage of the sea surface height variability and the baroclinic structure of the mainstream Kuroshio in the East China Sea, the Ryukyu Current east of the Ryukyu's, and the Kuroshio recirculation. An attractive approach of the KOP is a development of a new data acquisition system via acoustic telemetry of the observational data. The monitoring system will provide observations for assimilation into extensive numerical models of the ocean circulation, targeting the real-time monitoring of the Japanese coastal waters.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.256-261
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• 1999

Global vegetation change is one of major global concerns. Remote sensing images provide an efficient and useful data source to estimate global vegetation covers, and a number of methods have been proposed to estimate them. Among them, the NDVI is one of the most popular indices, and it is_easy to calculate with simple image computing. However, this index is very much affected by the radiometric environment of sensing such as atmospheric conditions and the sun illumination angle. Therefore, it is not appropriate to apply the NDVI to investigate seasonal changes. This paper discusses these problems and proposes an alternative index, MODVI(Modified Vegetation Index), that is less affected by radiometric environment changes. An experiment was conducted to compare these two indices using temporal Landsat TM sub-scenes.

• 한국지구과학회지
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• 제36권1호
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• pp.82-89
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• 2015

전지구 해양 해빙 예측시스템인 NEMO-CICE/NEMOVAR의 해빙 초기조건의 특성을 2013년 6월부터 2014년 5월까지 북극영역에 대하여 분석하였다. 이를 위하여 관측 자료와 재분석 자료를 모델의 초기조건과 비교하였다. 모델 초기조건은 관측에서 나타나는 해빙 면적과 해빙 두께의 월 변동을 잘 보이는 반면, 분석 기간 동안 관측과 재분석 자료보다 북극의 해빙 면적을 좁게, 해빙 두께를 얇게 나타내었다. 모델 초기조건의 북극 해빙 면적이 좁은 것은 해빙의 경계 지역에서 해빙 농도 초기조건이 약 20% 정도 재분석자료보다 낮기 때문이다. 또한 북극 평균 해빙 두께가 얇게 나타나는 이유는 연중 두꺼운 해빙이 유지되는 그린란드 및 북극 군도와 인접한 북극해 영역에서 모델의 초기조건이 약 60 cm 정도 얇기 때문이다.

• 대기
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• 제30권4호
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• pp.405-420
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• 2020

In this study, we investigate the predictability of intraseasonal monthly temperature and precipitation variations using hindcast datasets from eight global circulation models participating in the operational multi-model ensemble (MME) seasonal prediction system of the Asia-Pacific Economic Cooperation Climate Center for the 1983~2010 period. These intraseasonal monthly variations are defined by categorical deterministic analysis. The monthly temperature and precipitation are categorized into above normal (AN), near normal (NN), and below normal (BN) based on the σ-value ± 0.43 after standardization. The nine patterns of intraseasonal monthly variation are defined by considering the changing pattern of the monthly categories for the three consecutive months. A deterministic and a probabilistic analysis are used to define intraseasonal monthly variation for the multi-model consisting of numerous ensemble members. The results show that a pattern (pattern 7), which has the same monthly categories in three consecutive months, is the most frequently occurring pattern in observation regardless of the seasons and variables. Meanwhile, the patterns (e.g., patterns 8 and 9) that have consistently increasing or decreasing trends in three consecutive months, such as BN-NN-AN or AN-NN-BN, occur rarely in observation. The MME and eight individual models generally capture pattern 7 well but rarely capture patterns 8 and 9.

• 대기
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• 제34권2호
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• pp.177-185
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• 2024

As increasing global interest in renewable energy due to the ongoing climate crisis, there is a growing need for efficient technologies to manage such resources. This study focuses on the predictive skill of daily solar power generation using weather observation and forecast data. Meteorological data from the Korea Meteorological Administration and solar power generation data from the Korea Power Exchange were utilized for the period from January 2017 to May 2023, considering both inland (Daejeon) and coastal (Busan) regions. Temperature, wind speed, relative humidity, and precipitation were selected as relevant meteorological variables for solar power prediction. All data was preprocessed by removing their systematic components to use only their residuals and the residual of solar data were further processed with weighted adjustments for homoscedasticity. Four models, MLR (Multiple Linear Regression), RF (Random Forest), DNN (Deep Neural Network), and RNN (Recurrent Neural Network), were employed for solar power prediction and their performances were evaluated based on predicted values utilizing observed meteorological data (used as a reference), 1-day-ahead forecast data (referred to as fore1), and 2-day-ahead forecast data (fore2). DNN-based prediction model exhibits superior performance in both regions, with RNN performing the least effectively. However, MLR and RF demonstrate competitive performance comparable to DNN. The disparities in the performance of the four different models are less pronounced than anticipated, underscoring the pivotal role of fitting models using residuals. This emphasizes that the utilized preprocessing approach, specifically leveraging residuals, is poised to play a crucial role in the future of solar power generation forecasting.

• 한국지구과학회지
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• 제35권7호
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• pp.537-542
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• 2014

GRACE는 2002년 발사된 이래로 지하수, 빙하, 해수면의 변동에 의한 지구의 질량 재배치를 관측해오고 있다. GRACE 관측으로부터 추정된 지구 중력 모델은 기압보정을 거쳐 대기 질량이 제거된 지구 표면과 그 하부의 질량 변화를 나타낸다. 그러나 대기 총 질량은 지표면과 대기 사이의 물 교환에 의해 변한다. 그 결과 GRACE 중력 모델은 구면 조화 함수의 계수 degree 0, order 0 ($C_{00}$)에 해당하는 총 대기 질량 변화에 관련된 중력 스펙트럼을 가져야 한다. 주로 계절적인 시간 척도 안에서 변하는 수증기 때문에 $C_{00}$의 변화(${\delta}C_{00}$)는 특히 해수면의 계절적 변동과 북반구와 남반구 사이의 질량 균형에 매우 중요하다. 이 결과는 ${\delta}C_{00}$가 기후변동과 관련된 대륙 규모의 질량 변화 연구에 꼭 고려되어야 함을 뜻한다.

• 대한원격탐사학회지
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• 제37권6_1호
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• pp.1767-1772
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• 2021

장기간에 걸친 전 지구적인 위성관측 지표면 알베도 자료는 전 지구 기후 및 환경의 변화 감시에 활발히 이용되고 있으며 그 활용도와 중요성이 크다. 우리나라의 경우 정지궤도위성 천리안위성 1호(Communication, Ocean and Meteorological Satellite, COMS) MI(Meteorological Imager) 센서와 천리안위성 2A호(GEO-KOMPSAT-2A, GK-2A) AMI (Advanced Meteorological Imager) 센서의 세대교체를 통해 지속적인 지표면 알베도 산출물의 확보가 가능하다. 그러나 COMS/MI 및 GK-2A/AMI의 지표면 알베도 산출물은 센서 및 알고리즘의 차이로 인해 산출물 간의 차이가 존재한다. 따라서 COMS/MI와 GK-2A/AMI 지표면 알베도 산출 기간을 확장하고 지속적인 기후변화 감시 연계성 확보를 위해 두 위성 산출물 간의 오차 분석이 선행되어야 한다. 본 연구에서는 COMS/MI 및 GK-2A/AMI 지표면 알베도 자료의 중복기간을 대상으로 지상관측자료 AERONET (Aerosol Robotic Network)와 타 위성자료 GLASS (Global Land Surface Satellite)와 함께 비교 분석하였다. 오차 분석 결과 AERONET과의 검증에서 COMS/MI의 평균 제곱근 오차(Root Mean Square Error, RMSE)가 0.043로 GK-2A/AMI의 RMSE인 0.015보다 높게 나타났다. 또한 GLASS와 비교하였을 때 COMS/MI의 RMSE는 0.029로 GK-2A/AMI의 0.038보다 낮게 나타났다. 이러한 오차특성을 이해하고 COMS/MI 및 GK-2A/AMI의 지표면 알베도 자료를 사용할 때 장기간 기후변화 감시에 적극적으로 활용할 수 있을 것이다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1236-1238
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• 2003

The Earth's total magnetic field was extracted from on board TAM (Three Axis Magnetometer) observations of KOMPSAT-1 satellite between June 19th and 21st, 2000. In the pre-processing, the TAM's telemetry data were transformed from ECI (Earth Centered Inertial frame) to ECEF (Earth Centered Earth Fixed frame) and then to spherical coordination, and self-induced magnetic field by satellite bus itself were removed by using an on-orbit magnetometer data correction method. The 2-D wavenumber correlation filtering and quadrant-swapping method were applied to the pre-processed data in order to eliminate dynamic components and track-line noise, respectively. Then, the spherical harmonic coefficients are calculated from KOMPSAT-1 data. To test the validity of the TAM's geomagnetic field, Danish/NASA/French ${\phi}$rsted satellite's magnetic model and IGRF2000 model were used for statistical comparison. The correlation coefficient between ${\phi}$rsted and TAM is 0.97 and IGRF and TAM is 0.96. It was found that the data from on board magnetometer observations for attitude control of Earth-observing satellites can be used to determinate the Earth's total magnetic field and that they can be efficiently used to upgrade the global geomagnetic field coefficients, such as IGRF by providing new information at various altitudes with better temporal and spatial coverage.