• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.383-383
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• 2017

간척지는 바다와 접하는 하구언, 개벌로 이루어진 해안 등을 농공상업용지로 개간한 토지로서 간척지 이용에 있어 가장 우선적으로 용수공급 방안 수립이 고려되어야 한다. 해안유출지하수(submarine groundwater discharge)는 지하수 담수체가 존재하는 마지막 장소로 염해가 없는 청정수질 용수이다. 해안유출지하수 발생 구간을 탐지하기 위해 실측자료의 시공간적 한계를 극복할 수 있는 인공위성 영상을 활용한 원격탐사 기법을 이용하여 광역규모의 다양한 자료를 이용하고자 한다. MODIS (Moderate-Resolution Imaging Spectroradiometer)는 지구 생물권 활동에 관한 자료를 제공하는 미항공우주국 Terra EOS (Earth Observation system)위성의 주센서로 해양, 육상과 대기 분야에 적용이 가능한 다목적 센서이다. MODIS는 36개의 밴드를 이용하여 대기, 지표, 해양 관련 다양한 정보들을 제공하고 있다. 본 연구에서는 간척지의 효율적인 용수공급을 위한 해안유출지하수의 최적 개발 및 이용을 위해 MODIS MOD11 product 지표면온도(Land Surface Temperature; LST), MODIS MOD13 product 식생지수(Normalized Difference Vegetation Index; NDVI), 기상청의 지중온도와 실측자료를 이용하여 새만금 간척지를 대상으로 해안유출지하수 발생 구간을 탐지하고자 한다.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.4
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• pp.145-157
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• 2015

In 2015, drought was at the worst stage of devastation in Soyanggang Dam watershed. The purpose of this study is to trace the drought area around Soyanggang dam watershed by using Terra MODIS image because it has the ability of spatio-temporal dynamics. The MODIS indices, which included the enhanced vegetation index (NDVI), were extracted from MODIS product MOD13 16-day composite datasets with a spatial resolution of 250m from 2010.01.01 to 2015.06.30. We found that application of Vegetation Condition Index (VCI) and Standardized Vegetation Index (SVI) was suitable for monitoring the drought area. The result can be used to acquire the drought data scattered and demonstrate the potential for the use of MODIS data for temporal and spatial detection of drought effects.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.3
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• pp.27-41
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• 2017

The purpose of this study is to diagnose the possibility of future drought expression by late March dryness in rice paddy areas using Terra MODIS NDVI (Normalized Difference Vegetation Index). We tested the degree of dryness by comparing the 2000-2015 average NDVI with yearly NDVI, which we name DCI (Dry Condition Index). The 16-day interval DCIs from March 6 to May 25 were evaluated with spatio-temporal expression of South Korea. In particular, we find that the DCI for April 7 (March 23 to April 7) offered reasonable prediction of paddy dryness during drought years. The April 7 DCI value for dry conditions ranged from 0.04 to 0.08 while the DCI for normal conditions ranged from -0.04 to 0.01. The DCI can be one of the indicators used to evaluate the dryness of rice paddy areas at the beginning of the spring season.

• Journal of Korea Water Resources Association
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• v.45 no.8
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• pp.755-765
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• 2012

The Land Surface Temperature (LST) is one of the significant factors to understand the water and energy cycles between the land surface and atmosphere. However, few previous studies for spatio-temporal variations of LST has been investigated. In this study, we conducted comparative analyses between the Communication, Ocean and Meteorological Satellite (COMS) and MOderate-Resolution Imaging Spectroradiometer (MODIS) LST data. We compared COMS data with observations to identify the accuracy and found relative underestimated patterns of the COMS data as compared to observations. We also found that COMS LST were underestimated in compare to MODIS LST. The Terra LST was verified to have more similar trends with the COMS LST rather than Aqua LST. While we identified the applicability of COMS based on the results of similar tendencies of two comparisons, more intensive validation research at a variety of field conditions should be conducted to gurantee current COMS LST.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.1
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• pp.1-12
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• 2015

This study is to analyze the heavy snowfall vulnerable area of snow load design criteria for greenhouse, cattle shed and building using ground measured snow depth data and Terra MODIS snow cover area(SCA). To analyze the heavy snowfall vulnerable area, Terra MODIS satellite images for 12 years(2001-2012) were used to obtain the characteristics of snow depth and snow cover areas respectively. By comparing the snow load design criteria for greenhouse(cm), cattle shed($kg/m^2$), and building structure($kN/m^2$) with the snow depth distribution results by Terra MODIS satellite images, the facilities located in Jeolla-do, Chungcheong-do, and Gangwon-do areas were more vulnerable to exceed the current design criteria.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.6
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• pp.101-115
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• 2021

The purpose of this study is to evaluate the compatibility of the vegetation index between the two satellites and the applicability of agricultural monitoring by comparing and verifying NDVI (Normalized Difference Vegetation Index) based on Sentinel-2 and Terra MODIS (Moderate Resolution Imaging Spectroradiometer). Terra MODIS NDVI utilized 16-day MOD13Q1 data with 250 m spatial resolution, and Sentinel-2 NDVI utilized 10-day Level-2A BOA (Bottom Of Atmosphere) data with 10 m spatial resolution. To compare both NDVI, Sentinel-2 NDVIs were reproduced at 16-day intervals using the MVC (Maximum Value Composite) technique. As a result of time series NDVIs based on two satellites for 2019 and compare by land cover, the average R² (Coefficient of determination) and RMSE (Root Mean Square Error) of the entire land cover were 0.86 and 0.11, which indicates that Sentinel-2 NDVI and MODIS NDVI had a high correlation. MODIS NDVI is overestimated than Sentinel-2 NDVI for all land cover due to coarse spatial resolution. The high-resolution Sentinel-2 NDVI was found to reflect the characteristics of each land cover better than the MODIS NDVI because it has a higher discrimination ability for subdivided land cover and land cover with a small area range.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.612-615
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• 2005

Korea Aerospace Research Institute(KARl) has been receiving Terra and Aqua MODIS data at ground station of Daejeon since July 2002. MODIS data can cover whole East Asia including the Korean Peninsula, Japan and The East China each almost scene and is monitoring ocean, atmosphere and land. By this time, over two thousand scenes have been archived including Terra and Aqua in the storage system and they occupied about over 10TB of disk space. In this study, Web-Downloading system of MODIS data developed on WWW is including following main functions: spectral subset (250m, 500m, 1000m chnnels) Level 1B data of HDF format, result display, ftp download and statistic viewer etc. Users using this system can directly download MODIS data on WWW with a few input parameters. This system is available via the Internet URL after October 2005 on the following, 'http://webmodis.kari.re.kr/'

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.693-695
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• 2004

This study is a comparative analysis of chlorophyll a retrievals in the JES from SeaWiFS and MODIS/Terra. SeaWiFS and MODIS/Terra data over period from 2000 through 2003 were compared. The chlorophyll concentration from the SeaWiFS was generally higher than that from MODIS during the period. There are some possible causes for such discrepancy: differences in the sensor sensitivity, chlorophyll algorithms, and atmospheric correction algorithms. We checked some of these possibilities. We also compared the data from other regions. The deviation between the two data sets was highly correlated with chlorophyll concentrations Atmospheric corrections seem the major cause of the discrepancy.

• 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.

• Korean Journal of Remote Sensing
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• v.25 no.3
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• pp.243-253
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• 2009

For the last 14 years, space-borne satellite SAR system such as RADARSAT-1, ERS-2, and ENVISAT ASAR have provided a continuous observation over the ocean. However, the data acquired from those systems were limited to C-band frequency until the advent of the first spacebome German X-band SAR system TerraSAR-X in 2007. Korea is also planning to launch the nation's first X-band SAR satellite (KOMPSAT-5) in 2010. It is timely and necessary to develop X-band models for estimating geophysical parameters from these X-band SAR systems. In this study, X-band wind retrieval model was investigated and developed based on numerical ocean scattering model (radar backscattering model and hydrodynamic interaction model). Although these models have not yet been tested and validated for broad ranges of wind conditions, the estimated wind speeds from TerraSAR-X data show generally good agreement with in-situ measurements.