• Journal of Astronomy and Space Sciences
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• 제29권4호
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• pp.407-411
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• 2012

Space-borne remote sensing is an effective and inexpensive way to identify crop fields and detect the crop condition. We examined the multi-temporal spectral characteristics of rice fields in South Korea to detect their phenological development and condition. These rice fields are compact, small-scale parcels of land. For the analysis, moderate resolution imaging spectroradiometer (MODIS) and RapidEye images acquired in 2011 were used. The annual spectral tendencies of different crop types could be detected using MODIS data because of its high temporal resolution, despite its relatively low spatial resolution. A comparison between MODIS and RapidEye showed that the spectral characteristics changed with the spatial resolution. The vegetation index (VI) derived from MODIS revealed more moderate values among different land-cover types than the index derived from RapidEye. Additionally, an analysis of various VIs using RapidEye satellite data showed that the VI adopting the red edge band reflected crop conditions better than the traditionally used normalized difference VI.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.75-77
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• 2003

The spatial distribution of snow cover area is a crucial input to models of hydrology and climate in alpine and other seasonally snow covered areas.The objective in our study is to develop a rapidly automatic and high accuracy snow cover mapping algorithm applicable for the Tibetan Plateau which is the most sensitive about climatic change. Monitoring regional snow extent reqires higher temoral frequency-moderate spatial resolution imagery.Our algorithm is based AVHRR and MODIS data and will provide long-term fraction snow cover area map.We present here a technique is based on the multiple endmembers approach and by taking advantages of current approaches, we developed a technique for automatic selection of local reference spectral endmembers.

• 대한원격탐사학회지
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• 제35권4호
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• pp.609-616
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• 2019

Land surface temperature ($T_s$) is a critical variable for understanding the surface energy exchange between land and atmosphere. Using the data measured from micrometeorological flux towers, three types of $T_s$, obtained using a thermal-infrared radiometer (IRT), a net radiometer, and an equation for sensible heat flux, were compared. The $T_s$ estimated using the net radiometer was highly correlated with the $T_s$ obtained from the IRT. Both values acceptably fit the $T_s$ from the Terra/MODIS (Moderate Resolution Imaging Spectroradiometer)satellite. These results will enhance the measurement of land surface temperatures at various scales. Further, they are useful for understanding land surface energy partitioning to evaluate and develop land surface models and algorithms for satellite remote sensing products associated with surface thermal conditions.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2005년도 추계학술대회 논문집
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• pp.523-524
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• 2005

• 한국수자원학회논문집
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• 제45권8호
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• pp.755-765
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• 2012

지표면 온도는 수문기상학에서 매우 중요한 인자로써 지면-대기의 상호순환을 이해하는 데 필수적인 요소이다. 따라서 지표면 온도를 정확하게 산출하기 위한 연구가 이루어지고 있다. 그러나 국내에서는 현재까지 시 공간적으로 일정한 자료를 대상으로 한 연구가 미흡한 상황이다. 본 연구에서는 국내 최초의 정지궤도 위성인 Communication, Ocean and Meteorological Satellite (COMS)의 지표면 온도 자료를 사용하여 MODerate-resolution Imaging Spectroradiometer (MODIS) 센서를 탑재한 위성(Terra/Aqua)에서 제공되는 지표면 온도와 비교 분석을 실시하였다. 또한, COMS 자료의 정확성 확인을 위하여 지상관측지점의 자료와 비교하였다. 그 결과 MODIS와의 비교에서는 COMS가 Aqua/Terra에 비하여 전체적으로 과소 산정되었으며, Aqua보다는 Terra와 비슷한 경향을 가지고 있는 것을 확인할 수 있었다. 지상 관측 일평균자료와의 비교에서도 COMS가 과소 산정되는 것으로 나타났다. 각각의 오차는 알고리즘 사용 인자의 차이, 자료의 시간적 차이, 외부적인 요인 등으로 인해 발생하는 것으로 판단된다. 그러나 전체적인 경향성이 비슷한 것으로 나타나 COMS의 활용 가능성을 확인할 수 있었으며, 추후보다 정확한 검 보정에 대한 연구가 필요한 실정이다.

• 대한원격탐사학회지
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• 제32권1호
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• pp.25-38
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• 2016

With the increasing need for high temporal resolution satellite imagery for monitoring land surfaces, this study evaluated the temporal resolution of the NDVI composites from Geostationary Ocean Color Imager (GOCI) data. The GOCI is the first geostationary satellite sensor designed to provide continuous images over a $2,500{\times}2,500km^2$ area of the northeast Asian region with relatively high spatial resolution of 500 m. We used total 2,944 hourly images of the GOCI level 1B radiance data obtained during the one-year period from April 2011 to March 2012. A daily NDVI composite was produced by maximum value compositing of eight hourly images captured during day-time. Further NDVI composites were created with different compositing periods ranging from two to five days. The cloud coverage of each composite was estimated by the cloud detection method developed in study and then compared with the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua cloud product and 16-day NDVI composite. The GOCI NDVI composites showed much higher temporal resolution with less cloud coverage than the MODIS NDVI products. The average of cloud coverage for the five-day GOCI composites during the one year was only 2.5%, which is a significant improvement compared to the 8.9%~19.3% cloud coverage in the MODIS 16-day NDVI composites.

• 한국환경복원기술학회지
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• 제9권6호
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• pp.1-12
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• 2006

Remote sensing cannot provide a direct measurement of vegetation index (VI) but it can provide a reasonably good estimate of vegetation index, defined as the ratio of satellite bands. The monitoring of vegetation in nearby urban regions is made difficult by the low spatial resolution and temporal resolution image captures. In this study, enhancing spatial resolution method is adapted as to improve a low spatial resolution. Recent studies have successfully estimated normalized difference vegetation index (NDVI) using improved resolution method such as from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard EOS Terra satellite. Image enhancing spatial resolution is an important tool in remote sensing, as many Earth observation satellites provide both high-resolution and low-resolution multi-spectral images. Examples of enhancement of a MODIS multi-spectral image and a MODIS NDVI image of Cheongju using a Landsat TM high-resolution multi-spectral image are presented. The results are compared with that of the IHS technique is presented for enhancing spatial resolution of multi-spectral bands using a higher resolution data set. To provide a continuous monitoring capability for NDVI, in situ measurements of NDVI from paddy field was carried out in 2004 for comparison with remotely sensed MODIS data. We compare and discuss NDVI estimates from MODIS sensors and in-situ spectroradiometer data over Ochang plain region. These results indicate that the MODIS NDVI is underestimated by approximately 50%.

• 대한원격탐사학회지
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• 제38권6_1호
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• pp.1035-1046
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• 2022

이 연구에서는 토지 피복 분류를 위한 다중 해상도 자료 융합의 적용성을 평가하였다. 여기서 다중 해상도 자료 융합 모델로는 spatial time-series geostatistical deconvolution/fusion model (STGDFM)을 적용하였다. 연구 지역은 미국 Iowa 주의 일부 농경 지역으로 선정하였으며, 대상 지역의 규모를 고려해 다중 해상도 자료 융합의 입력 자료로 Moderate Resolution Imaging Spectroradiometer (MODIS) 및 Landsat 영상을 사용하였다. 이를 바탕으로 STGDFM 적용해 Landsat 영상이 결측된 시기에서 가상의 Landsat 영상을 생성하였다. 그리고 획득한 Landsat 영상과 함께 STGDFM의 융합 결과를 입력 자료로 사용해 토지 피복 분류를 수행하였다. 특히 다중 해상도 자료 융합의 적용성 평가를 위해 획득한 Landsat 영상만을 이용한 분류 결과와 Landsat 영상 및 융합 결과를 모두 이용한 분류 결과를 비교 평가하였다. 그 결과, Landsat 영상만을 이용한 분류 결과에서는 대상 지역의 주요 토지 피복인 옥수수와 콩 재배지에서 혼재 양상이 두드러지게 나타났다. 또한 건초 및 곡물 지역과 초지 지역 등 식생 피복 간의 혼재 양상도 큰 것으로 나타났다. 반면 Landsat 영상 및 융합 결과를 이용한 분류 결과에서는 옥수수와 콩 재배지의 혼재 양상과 식생 피복 간의 혼재 양상이 크게 완화되었다. 이러한 영향으로 Landsat 영상 및 융합 결과를 이용한 분류 결과에서 분류 정확도가 약 20%p 향상되었다. 이는 STGDFM을 통해 MODIS 영상이 갖는 시계열 분광 정보를 융합 결과에 반영하면서 Landsat 영상의 결측을 보완할 수 있었고, 이러한 시계열 분광 정보가 분류 과정에 결합되면서 오분류를 크게 줄일 수 있었던 것으로 판단된다. 본 연구 결과를 통해 토지 피복 분류에 다중 해상도 자료 융합이 효과적으로 적용될 수 있음을 확인하였다.

• Asian Journal of Atmospheric Environment
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• 제12권3호
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• pp.193-203
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• 2018

The operational aerosol retrieval algorithm for the Moderate Resolution Imaging Spectroradiometer (MODIS) measurements was recently updated and named collection 6 (C6). The C6 MODIS aerosol algorithm, a substantially improved version of the collection 5 (C5) algorithm, uses an enhanced aerosol optical thickness(AOT) retrieval process consisting of new surface reflection and aerosol models. This study reports on the estimation and validation of the two latest versions, the C5 and C6 MODIS aerosol products over the East Asian region covering $20^{\circ}N$ to $56^{\circ}N$ and $80^{\circ}E$ to $150^{\circ}E$. This study also presents a comparative validation of the two versions(C5 and C6) of algorithms with different methods(Dark Target(DT) and Deep Blue (DB) retrieval methods) from the Terra and Aqua platforms to make use of the Aerosol Robotic Network (AERONET) sites for the years 2000-2016. Over the study region, the spatially averaged annual mean AOT retrieved from C6 AOT is about 0.035 (5%) less than the C5 counterparts. The linear correlations between MODIS and AERONET AOT are R = 0.89 (slope = 0.86) for C5 and R = 0.95 (slope = 1.00) for C6. Moreover, the magnitude of the mean error in C6 AOT-the difference between MODIS AOT and AERONET AOT-is 40% less than that in C5 AOT.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 춘계학술발표회논문집
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• pp.251-257
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• 2004

The Electro-Optical Camera(EOC) image of the first Korea Multi-Purpose Satellitel(KOMPSAT-1) has both high resolution and convenient acquisition of research data, but on the other hand it has a defect of one band image. Fortunately, the multispectral Moderate Resolution Imaging Spectroradiometer (MODIS) image data are receiving every day at the Korea Aerospace Research Institute (KARI). Therefore, this paper performed an effective merging for survey of reclaimed land using the high-resolution (6.6m) KOMPSAT-1 EOC image and the multispectral MODIS image data. According this paper prepared map of reclaimed lands in Western Coast of North Korea as quantitative(position and form) survey of reclaimed lands of North Korea using merged image. The use of KOPSAT-1 EOC image and MODIS images was found to be economical such using of large scale areas as reclaimed land or according easy to collect information and such north korea as inaccessible areas like as receiving every day.