• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.3
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• pp.150-160
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• 2005

In this study, the spatiotemporal surface temperature changes were analyzed in the Korean peninsula. The surface temperature variation was estimated using the split window method and NOAA/AVHRR data in 1991, 1995 and 2000. The ranges of differences in temperature between day time and night time were $3-15^{\circ}C$ around the peninsula. The differences in seasonal variations and yearly fluctuations in big cities were lower than those in rural areas and showed clearly the effects of the urbanization. The characteristics of urban heat affects were further determined based on the day and night time temperature comparison on Busan metropolitan area between these periods. Finally, the future use of this technology was suggested for the urban environmental planning.

• 한국해양학회지
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• v.30 no.6
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• pp.543-549
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• 1995

The inverse method has been used to estimate a surface velocity field from sequential AVHRR/SST data. In the model, equation system was composed of heat equation and horizontal divergence minimization and the velocity field contained in the advective term of the heat equation, which was linearized in grid system, was estimated. A constraint was the minimization of horizontal divergence with weighting factor and introduced to compensate the null space(Menke, 1984) of the velocity solutions for the heat equation. The experiments were carried out to set up the range of weighting factor and the matrix equation was solved by SVD(Singular Value Decomposion). In the experiment, the scales of horizontal temperature gradient and divergence of synthetic velocity field were approximated to those of real field. The neglected diffusive effect and the horizontal variation of heat flux in the heat equation were regarded as random temperature errors. According to the result of experiments, the minimum of relative error was more desirable than the minimum of misfit as the criteria of setting up the weighting factor and the error of estimated velocity field became small when the weighting factor was order of $10^{-1}$

• Korean Journal of Remote Sensing
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• v.23 no.2
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• pp.119-124
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• 2007

The few observed data related snowmelt was the major cause of difficulty in extracting snowmelt factors such as snow cover area, snow depth and depletion curve. Remote sensing technology is very effective to observe a wide area. Although many researchers have used remote sensing for snow observation, there were a few discussions on the characteristics of spatial and temporal variation. Snow cover maps were derived from NOAA AVHRR images for the winter seasons from 1997 to 2006. Distributed snow depth was mapped by overlapping between snow cover maps and interpolated snowfall maps from 69 meteorological observation stations. Model parameters (Snow Cover Area: SCA, snow depth, Snow cover Depletion Curve: SDC) building for 5 major watersheds in South Korea. Especially SDC is important parameter of snowmelt model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3B
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• pp.295-303
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• 2010

The variability of vegetation is strongly related to the variability of hydrometeorological factors such as precipitation, temperature, runoff and so on. Analysis of the variability of vegetation will aid to understand the regional impact of climate change. Thus we analyzed the spatial-temporal variability of NOAA(National Oceanic and Atmospheric Administration)/AVHRR(Advanced Very High Resolution Radiometer) NDVI(Normalized Difference Vegetation Index). In the results from Mann-Kendall test, there is no significant linear trend of annual NDVI from 1982 to 2006 in the most area except the downward trend on the significance level 90% in the Guem-river basin area. In addition, using EOF(Empirical Orthogonal Function) analysis, the variability of NDVI in the region of higher latitude and altitude is higher than that in the other region since the spatial variability of NDVI follows the latitudinal gradient. Also we could get higher NDVI in June, July, August and September. We had the highest NDVI in Han-river basin area and the lowest in Je-Ju island.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.127-131
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• 2005

NOAA/AVHRR 위성영상을 이용하여 기상학적 가뭄을 평가하고, SWSI (Surface Water Supply Index)를 보완한 MSWSI (Modified SWSI)를 이용하여 전국을 32개 유역으로 분할 및 적용하여 수문학적인 가뭄을 평가하고, 농업용 저수지의 유입량 및 저수량을 이용하여 용수구역 단위의 농업가뭄을 평가하였다. 기상학적 가뭄평가를 위해서 NOAA/AVHRR 위성영상으로부터 추출된 실제증발산량과 Hamon 방법에 의하여 산정된 잠재증발산량을 이용하여 기후학적 물수지 분석을 수행하고 가뭄파악을 위한 지표인 습윤지표 분포도를 작성하였다. 수문학적 가뭄평가를 위해서 강우량, 하천유량, 댐유입량, 지하수위 자료를 이용하여 1974년부터 2001년까지의 유역단위 MSWSI 값을 산정하였다. 농업 가뭄을 평가하기 위하여 안성시 고삼저수지의 저수량과 SLURP 모형을 이용하여 산정한 유입량으로서 안고용수구역에 대하여 농업 가뭄을 평가하였다.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.31-33
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• 2004

Two receiving systems were established at the Asian Center for Research on Remote Sensing (ACRoRS) to receive remote sensing data from NOAA AVHRR and Terra/Aqua MODIS sensors in October 1997 and May 2001, respectively. The data, which has been received in the research center, are very important to support and promote the remote sensing research activities for global environmental issues in Asia. Since the day of the establishment, many research and applications, which used these data, have been conducted. The data sets have been provided to researchers and users in many countries in the region to conduct research, to strengthen the research collaboration and education.

• Proceedings of the KSRS Conference
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• v.1
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• pp.110-113
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• 2006

This study is to grasp and analyse the temporal and spatial distribution of record-breaking heavy snowfall rarely occurred in the middle and southwest region of South Korea during March of 2004 and December of 2005 respectively. Snow cover area was extracted using the channels 1, 3 and 4 of NOAA AVHRR images and the snow depth distribution was spatially interpolated using snowfall data of meteorological stations. Using administration boundary and Digital Elevation Model from 1:5,000 NGIS digital map, the snowfall impact was assessed spatially and compared with the reports at that time.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.3
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• pp.241-247
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• 1995

A time mean surface velocity field was estimated from AVHRR/SST in the Korea Strait. Time duration of SST data set was not different from tidal period and tidal elimination was investigated. The velocity field was estimated by inverse method and compared with results of ADCP observation and results of Odamaki(1989). In accordance with results. tidal component was eliminated partially in case that there were a little difference between total time interval of 557 data set and tidal period.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.281-284
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• 2004

광범위한 면적의 토지피복분류를 관찰하는데 유용하게 사용되고 있는 NOAA AVHRR 자료는 자료의 방대한 양과 구름에 의한 영향을 없애기 위하여 일반적으로 MVC(Maximum Value Composite) 처리를 하여 사용한다. 그러나 수신당시의 여러 가지 환경인자(구름, 저주파 노이즈, 산란, 구름의 그림자 등)에 의하여 각 채널의 패턴이 변화하여 오독을 할 위험성이 있다. 특히 그림자의 영향에 의해 측정치가 변화하는 NOAA 위성의 채널2영역에서는 이러한 특징이 두드러진다. 따라서 본 연구에서는 지상에서 실제로 측정한 자료를 기초로 하여 NOAA 영상자료에서 구름으로 인한 그림자의 영향에 관하여 조사하였고, 한 픽셀안에서 그림자의 영향이 60%이상이 될 경우에는 오독의 가능성이 높은 것으로 나타났다.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.670-672
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• 2003

The purpose of this study is to estimate monthly evapotranspiration (ET) using normalized difference vegetation index (NDVI) obtained from NOAA/AVHRR data sets. Actual evapotranspiration was evaluated by the complementary relationship (Morton, 1978, Brutsaert and Stricker, 1979), and monthly NDVI was obtained by maximum value composite method from daily NDVI images in the Korean peninsula for the year 2001. The monthly actual ETs for each land cover were compared with the monthly NDVIs to determine relationships between actual ET and NDVI for each land cover category. There was a high correlation between monthly NDVI and monthly averaged actual ET. This study presents an alternative approach for land surface evapotranspiration based on remote sensing techniques.