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‣ Wavelet analysis of MODIS time series to detect expansion and intensification of row-crop agriculture in Brazil

GALFORD, Gillian L.; MUSTARD, John F.; MELILLO, Jerry; GENDRIN, Aline; CERRI, Carlos C.; CERRI, Carlos E. P.
Fonte: ELSEVIER SCIENCE INC Publicador: ELSEVIER SCIENCE INC
Tipo: Artigo de Revista Científica
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Since 2000, the southwestern Brazilian Amazon has undergone a rapid transformation from natural vegetation and pastures to row-crop agricultural with the potential to affect regional biogeochemistry. The goals of this research are to assess wavelet algorithms applied to MODIS time series to determine expansion of row-crops and intensification of the number of crops grown. MODIS provides data from February 2000 to present, a period of agricultural expansion and intensification in the southwestern Brazilian Amazon. We have selected a study area near Comodoro, Mato Grosso because of the rapid growth of row-crop agriculture and availability of ground truth data of agricultural land-use history. We used a 90% power wavelet transform to create a wavelet-smoothed time series for five years of MODIS EVI data. From this wavelet-smoothed time series we determine characteristic phenology of single and double crops. We estimate that over 3200 km(2) were converted from native vegetation and pasture to row-crop agriculture from 2000 to 2005 in our study area encompassing 40,000 km(2). We observe an increase of 2000 km(2) of agricultural intensification, where areas of single crops were converted to double crops during the study period. (C) 2007 Elsevier Inc. All rights reserved.

‣ Extracting temporal and spatial distributions information about marine mucilage phenomenon based on Modis satellite images; a case study of the Tyrrhenian and the Adriatic Sea, 2010-2012

Gigliotti, Angelo
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Dissertação de Mestrado
Publicado em 28/02/2013 Português
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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.; A novel approach was used with data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to detect Marine Mucilage in tow different marine areas of the Italy (Campanian Seas and North Adriatic Sea) from 2010 to 2012. The approach involves first deriving a Mucilage Index (MI) based on the medium‐resolution (500 m) MODIS reflectance data correction of the ozone/gaseous absorption and Rayleigh scattering effects and then objectively determining the MI threshold value (0.05

‣ Detecção de cicatrizes de áreas queimadas baseada no modelo linear de mistura espectral e imagens índice de vegetação utilizando dados multitemporais do sensor MODIS/TERRA no estado do Mato Grosso, Amazônia brasileira

Anderson,Liana Oighenstein; Aragão,Luiz Eduardo Oliveira e Cruz de; Lima,André de; Shimabukuro,Yosio Edemir
Fonte: Instituto Nacional de Pesquisas da Amazônia Publicador: Instituto Nacional de Pesquisas da Amazônia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2005 Português
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O objetivo desta pesquisa foi avaliar os dados do sensor MODIS para detectar e monitorar cicatrizes de áreas recém queimadas. Utilizamos imagens da reflectância de superfície do sensor MODIS: produto MOD09 (dia 5 de outubro) e produto MOD13A1 (meses de outubro e novembro). Foi avaliada também uma série temporal de um ano dos índices de vegetação (IV) EVI e NDVI (produto MOD13A1). Uma imagem do sensor ETM+ (dia 5 de outubro) foi utilizada como base para a delimitação dos polígonos amostrais e avaliação dos dados MODIS devido a sua melhor resolução espacial. A metodologia focou na aplicação do modelo linear de mistura espectral nas imagens reflectância para a geração das imagens fração sombra. Análises de regressão foram efetuadas para comparação entre o percentual de sombra derivado da imagem ETM+ e das imagens MODIS. As alterações multitemporais nas imagens IV foram avaliadas com base no teste de Tukey. Os resultados mostraram que a imagem fração sombra gerada a partir do produto MOD09 apresentou um R² = 0,66 (p < 0,01) em relação aos dados ETM+. Para as imagens do produto MOD13A1 não foram identificadas relações significativas. Os IV dentro dos mesmos polígonos apresentaram uma variação sazonal durante o ano. No entanto...

‣ Synthesis of Satellite (MODIS), Aircraft (ICARTT), and Surface (IMPROVE, EPA-AQS, AERONET) Aerosol Observations over Eastern North America to Improve MODIS Aerosol Retrievals and Constrain Surface Aerosol Concentrations and Sources

Drury, Easan; Jacob, Daniel James; Spurr, Robert J. D.; Wang, Jun; Shinozuka, Yohei; Anderson, Bruce E.; Clarke, Antony D.; Dibb, Jack; McNaughton, Cameron; Weber, Rodney
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica
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We use an ensemble of satellite (MODIS), aircraft, and ground-based aerosol observations during the ICARTT field campaign over eastern North America in summer 2004 to (1) examine the consistency between different aerosol measurements, (2) evaluate a new retrieval of aerosol optical depths (AODs) and inferred surface aerosol concentrations ((PM_{2.5})) from the MODIS satellite instrument, and (3) apply this collective information to improve our understanding of aerosol sources. The GEOS-Chem global chemical transport model (CTM) provides a transfer platform between the different data sets, allowing us to evaluate the consistency between different aerosol parameters observed at different times and locations. We use an improved MODIS AOD retrieval based on locally derived visible surface reflectances and aerosol properties calculated from GEOS-Chem. Use of GEOS-Chem aerosol optical properties in the MODIS retrieval not only results in an improved AOD product but also allows quantitative evaluation of model aerosol mass from the comparison of simulated and observed AODs. The aircraft measurements show narrower aerosol size distributions than those usually assumed in models, and this has important implications for AOD retrievals. Our MODIS AOD retrieval compares well to the ground-based AERONET data (R = 0.84...

‣ Mapping of Fractional Forest Cover in Rondonia, Brazil with a Combination of Terra MODIS and Landsat TM Images.

LU, D.; BATISTELLA, M.; ALVES, D. HETRICK, S.; MORAN, E.
Fonte: In: LBA_ECO Science Team Meeting, 11., 2007, Salvador. Resumos... Salvador: LBA, 2007. Publicador: In: LBA_ECO Science Team Meeting, 11., 2007, Salvador. Resumos... Salvador: LBA, 2007.
Tipo: Resumo em anais de congresso (ALICE) Formato: p. 31-32.
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High deforstation rates in Amazonia have motivated considerable efforts to monitor land-cover changes based on satellite images and image porcesssing techniques. Most commonly, MODIS images are used to provide low-cost region-wide coverage at nearly monthly frequencies, but they offer offer only coarse resolution, Lsndsat TM has been used in a majority of studies for nearly two decades, but these, but these data are expensive, and provide, at best, yearly coverage because of clouds. Here, a new approach to estimate forest change is proposed based on the integration of TM and MODIS images. TM images are processed using a hybrid approach including spectral mixture, expert rules, and usupervised classification, to generate a reference forest image. Three fraction images are derived from MODIS surface reflectance data; expert rules are used to generate a refined vegetation image and regression is then develoned between the TM-derived forest and MODIS derived vegetation data to assess the fractional forest area. This approach was initially applied to 2004 MODIS and TM images from Rondônia, and the regression model was transferred to 2000 and 2006 MODIS images. A similar exercise was made in Pará state for the estimation of forest area in 2005. Compared to TM-derived reference data in Rondônia...

‣ Uso de imagens MODIS no mapeamento de bacias hidrográficas

Chrystiane de Moura Matos, Rafaella; Lucia Bezerra Candeias, Ana (Orientador)
Fonte: Universidade Federal de Pernambuco Publicador: Universidade Federal de Pernambuco
Tipo: Outros
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Esta pesquisa tem como enfoque mostrar aplicações do sensor MODIS (Moderate Resolution Spectroradiometer) e seus diferentes tipos de produtos. O MODIS foi concebido para análise de mudanças em escala global, possuindo assim diversas aplicações ambientais. Este sensor possui 36 bandas e 44 produtos para diferentes tipos de pesquisas. A resolução espacial das imagens MODIS varia de 250m a 1km dependendo da banda ou produto a ser analisado. O produto MOD13Q1 do nível 3 do sensor MODIS é um produto específico para aquisição de informações do NDVI (Índice de Vegetação por Diferença Normalizada), com resolução espacial de 250 m, e resolução espacial de 16 dias, e dispõe de dois índices de vegetação: NDVI e EVI (Enhanced Vegetation Index); Duas imagens com informações de atestamento da qualidade dos produtos NDVI e EVI (quality NDVI e quality EVI); Imagens de reflectância RED, BLUE, NIR e MIR;Três imagens referentes a forma de aquisição dos dados, correspondentes a ângulo de visada, ângulo zenital solar e azimute. Já produto MOD43B3 é um produto de albedo de superfície do MODIS e contém as sete primeiras bandas do sensor MODIS além de outras três bandas simuladas com larga faixa espectral. O MOD11 é um produto do nível 2 que fornece dados de temperatura da superfície terrestre (LST Land Surface Temperature) e emissividade (E) diárias da superfície terrestre com resolução espacial de 1 Km...

‣ Detalhamento de áreas de savana arborizada no bioma Cerrado a partir da análise de séries temporais MODIS EVI para o período de 2004 a 2008; Details of the savanna woodland in Cerrado based on the analysis of time series MODIS EVI for the period 2004 to 2008

PONTES, Marlon Nemayer Celestino de
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Geografia; Ciências Humanas Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Geografia; Ciências Humanas
Tipo: Dissertação Formato: application/pdf
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Land cover and land use maps are essentials for the effective territorial governance, environmental monitoring, and proper understanding of the structure and functioning of the ecosystems. In relation to the Cerrado biome, an important step in this direction was obtained with the PROBIO mapping (Projeto de Conservação e Utilização Sustentável da Diversidade Biológica Brasileira do Ministério do Meio Ambiente), which, based on the interpretation of high spatial resolution imagery (Landsat TM), acquired in 2001 and 2002, mapped the entire biome at the scale of 1:250.000, accorging to the 30 natural and 5 anthropic classes. Although this mapping allowed to know, at high accuracy and precision, the extension and distribution of the major land cover types, its updating and further detailing are necessary. A particular example of such need is the Arboreous Savanna class, which, according to the PROBIO map, occupies an area of about 415.642,58 km² (33,72% of all Cerrado remnant vegetation) and presents an marked variability, 20 to 70% in its arborescent layer. Assuming that the phytophisiognomic variations within this class yield distinct seasonal patterns, in this study we evaluated the potential of the MODIS EVI (enhanced vegetation index) imagery...

‣ Mapeamento de áreas queimadas no bioma cerrado a partir de dados MODIS MCD45A1; Monitoring burned areas in the cerrado from the data MODIS MCD45A1

Araújo, Fernando Moreira de
Fonte: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Geografia (IESA); Instituto de Estudos Socioambientais - IESA (RG) Publicador: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Geografia (IESA); Instituto de Estudos Socioambientais - IESA (RG)
Tipo: Dissertação Formato: application/pdf
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The Cerrado biome has many favorable characteristic, like soil, relief, and dense hydrography, for the development of mainly economic activity, as agriculture and pasture, this biome has suffered high human disturbance process. Along with human activities, the practice of burning was increased, particularly for the practice of grazing management, pest control, cleaning of areas for agricultural planting and others. The fires have several consequences for the biome, amongst them have increasing of temperature, decreasing rainfall, genetic impoverishment of natural species, increases the risk of respiratory diseases. In this research, for mapping burned areas in the Cerrado biome between 2002 to 2008 was used MCD45A1 MODIS product, which makes the mapping of burn scars globally scale. The result is that fires occur during the year in the Cerrado, reaching its peak between July to September, warm and dry period with the lowest relative humidity. The burned areas are located in larger amounts in the north-central part of the Cerrado, mainly in the expansion of agriculture in the states of Bahia, Piaui, Maranhao, Mato Grosso and Tocantins. However, the fires, based on mapping of the PROBIO Cerrado, occur in greater proportions in regions of natural vegetation cover (81.7%)...

‣ MODIS EVI and LST temporal response for discrimination of tropical land covers

Phompila, C.; Lewis, M.; Ostendorf, B.; Clarke, K.
Fonte: MDPI AG Publicador: MDPI AG
Tipo: Artigo de Revista Científica
Publicado em //2015 Português
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MODIS enhanced vegetation index (EVI) and land surface temperature (LST) are key indicators for monitoring vegetation cover changes in broad ecosystems. However, there has been little evaluation of these indices for detecting changes in a range of land covers in tropical regions. In this study, we investigated the characteristics and seasonal responses of LST and EVI for four different land covers in Lao tropical forests: native forest, rubber plantation, mixed wooded/cleared areas and agriculture. We calculated long-term averages of MODIS LST and EVI 16-day time series and compared their monthly transitions over the seven-year period from 2006 to 2012. We also tested whether these indices can be used to classify these four land covers. The findings demonstrate the complex interrelationship of LST and EVI and their monthly transitions for different land covers: they each showed distinctly different intra-annual LST and EVI variations. Native forests have the highest EVI, and the lowest LST throughout the year. In contrast, agricultural areas with little or no vegetation cover have the highest LST. The transition of LST/EVI for the land covers other than native forests showed marked seasonality. Linear discriminant analysis (LDA) showed that there was high overall accuracy of separation of land covers by these indices (86%). The encouraging results indicate that the combined use of MODIS LST and EVI holds promise for improving monitoring of changes in a Lao tropical forest.; Chittana Phompila...

‣ Cartografía de incendios forestales en Paraguay mediante imágenes AQUA-MODIS

Martín Isabel, M. Pilar; Rejalaga Noguera, Larissa K.
Fonte: Universidad de Alcalá. Servicio de Publicaciones Publicador: Universidad de Alcalá. Servicio de Publicaciones
Tipo: Artigo de Revista Científica Formato: application/pdf
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Uno de los principales problemas ambientales que se plantean actualmente a nivel mundial es la pérdida de los recursos forestales ocasionada por el fuego. La gran extensión y dificultad de acceso a muchas de las zonas afectadas, especialmente en zonas tropicales, hace difícil la cuantificación del daño que provocan los incendios forestales. La cartografía operativa de las áreas quemadas requiere disponer de métodos fiables y rápidos que permitan obtener resultados en un margen relativamente corto de tiempo y a una escala espacial y temporal adecuada para la gestión del fenómeno. La teledetección desde satélite supone una técnica adecuada para esta finalidad ya que proporciona datos de la superficie terrestre con una cobertura espacial y temporal suficientemente detallada y ofrece información espectral apropiada para la cartografía de áreas quemadas. En este trabajo se aborda el uso de imágenes procedentes del sensor AQUA-MODIS para la cartografía de áreas afectadas por incendios forestales en Paraguay. Se propone una metodología que combina productos MODIS con distintas resoluciones espaciales (500 y 250 metros) y espectrales (7 y 2 bandas) con el propósito de mejorar la capacidad de discriminación y delimitación de las zonas afectadas por incendios forestales en un ámbito tropical. La metodología propuesta nos permitió discriminar todos los incendios ocurridos en la zona de estudio con tamaño igual o superior a 150 hectáreas. La capacidad de discriminación resultó aceptable (en torno a los 60 %) para los incendios entre 100 y 125 hectáreas...

‣ Canopy structural and meteorological influences on CO2 exchange for MODIS product validation in a boreal jack pine chronosequence

Chasmer, Laura Elizabeth
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 3157533 bytes; application/pdf
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Previously disturbed and regenerating forests make up a significant proportion of the North American land area, and therefore play an important role in the exchanges of heat and trace gases between the terrestrial biosphere and the atmosphere. Assessment of local to global variability in CO2 exchanges by forests requires a combination of CO2 measurements made by eddy covariance (EC), field measurements, remote sensing data, and ecosystem models. The integration of these is problematic because of a mis-match in scale between measurement techniques. Despite the importance of regenerating forests on the global carbon balance, the processes affecting the carbon cycle within these forests is not well understood. Airborne scanning light detection and ranging (lidar) instruments provide new opportunities to examine three-dimensional forest characteristics from the level of individual trees to ecosystems and beyond. Lidar is therefore an effective link between plot measurements, eddy covariance, and low resolution remote sensing pixels. This thesis dissertation presents new science on the use of airborne lidar for evaluating remote sensing products within heterogeneous and previously clearcut ecosystems. The goals of this thesis were to first understand the processes affecting CO2 exchanges within a previously disturbed boreal jack pine chronosequence located in Saskatchewan...

‣ Análisis de series de tiempo de índice de vegetación EVI 2006-2011 para caracterizar el cultivo del arroz a partir de imágenes MODIS

Mendoza Riaño, Gonzalo Eduardo
Fonte: Universidad Militar Nueva Granada; Facultad de ingeniería; Especialización en geomática Publicador: Universidad Militar Nueva Granada; Facultad de ingeniería; Especialización en geomática
Tipo: Bacherlot thesis; Ensayo Formato: application/pdf
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El presente trabajo analiza la utilidad del índice de vegetación EVI del sensor MODIS, para explicar el uso del suelo agrícola específicamente la dinámica fenológica del cultivo del arroz en sistema secano en el Departamento del Meta. El índice mide el verdor de la vegetación es posible discriminar propiedades de la vegetación como, el área foliar, la clorofila y la estructura de la cubierta. La fenología del cultivo se evalúa a partir de la adquisición y superposición de 128 imágenes con una frecuencia de 16 días que calculan el índice de vegetación EVI entre 2006 y 2011, y mediante la evaluación de tres casos de uso, se realiza el perfil temporal de la serie y el análisis del índice. Luego de evaluar la información se encontró que el índice modela correctamente el ciclo fenológico del cultivo y permite conocer de manera remota características que solo era posible identificar realizando trabajo de campo; The present study analyzes the utility of vegetation index EVI of sensor MODIS, to explain the agricultural use of land, specifically for identifying the phenological dynamics in rice crops at department of Meta. The index evaluates the greenness of vegetation, through which it is possible to discriminate properties of vegetation...

‣ Global burned-land estimation in Latin America using MODIS composite data

Chuvieco E.; Opazo S.; Sione W.; Del Valle H.; Anaya J.; Di Bella C.; Cruz I.; Manzo L.; Lopez G.; Mari N.; Gonzalez-Alonso F.; Morelli F.; Setzer A.; Csiszar I.; Kanpandegi J.A.; Bastarrika A.; Libonati R.
Fonte: Universidade de Medellín Publicador: Universidade de Medellín
Tipo: Article; info:eu-repo/semantics/article
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This paper presents results of the AQL2004 project, which has been developed within the GOFC-GOLD Latin American network of remote sensing and forest fires (RedLatif). The project intended to obtain monthly burned-land maps of the entire region, from Mexico to Patagonia, using MODIS (moderate-resolution imaging spectroradiometer) reflectance data. The project has been organized in three different phases: acquisition and preprocessing of satellite data; discrimination of burned pixels; and validation of results. In the first phase, input data consisting of 32-day composites of MODIS 500-m reflectance data generated by the Global Land Cover Facility (GLCF) of the University of Maryland (College Park, Maryland, USA) were collected and processed. The discrimination of burned areas was addressed in two steps: searching for "burned core" pixels using postfire spectral indices and multitemporal change detection and mapping of burned scars using contextual techniques. The validation phase was based on visual analysis of Landsat and CBERS (China-Brazil Earth Resources Satellite) images. Validation of the burned-land category showed an agreement ranging from 30% to 60%, depending on the ecosystem and vegetation species present. The total burned area for the entire year was estimated to be 153 215 km2. The most affected countries in relation to their territory were Cuba...

‣ Estimation of Net Ecosystem Carbon Exchange for the Conterminous United States by Combining MODIS and AmeriFlux Data

Drake, Bert G.; Richardson, Andrew D.; Cook, David R.; Bolstad, Paul V.; Curtis, Peter S.; Zhuang, Qianlai; McNulty, Steve; Martin, Timothy A.; Matamala, Roser; Hadley, Julian L.; Suyker, Andrew E.; Ma, Siyan; Wofsy, Steven; Wharton, Sonia; Sun, Ge; Torn,
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
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Eddy covariance flux towers provide continuous measurements of net ecosystem carbon exchange (NEE) for a wide range of climate and biome types. However, these measurements only represent the carbon fluxes at the scale of the tower footprint. To quantify the net exchange of carbon dioxide between the terrestrial biosphere and the atmosphere for regions or continents, flux tower measurements need to be extrapolated to these large areas. Here we used remotely sensed data from the Moderate Resolution Imaging Spectrometer (MODIS) instrument on board the National Aeronautics and Space Administration's (NASA) Terra satellite to scale up AmeriFlux NEE measurements to the continental scale. We first combined MODIS and AmeriFlux data for representative U.S. ecosystems to develop a predictive NEE model using a modified regression tree approach. The predictive model was trained and validated using eddy flux NEE data over the periods 2000–2004 and 2005–2006, respectively. We found that the model predicted NEE well (r = 0.73, p < 0.001). We then applied the model to the continental scale and estimated NEE for each 1 km × 1 km cell across the conterminous U.S. for each 8-day interval in 2005 using spatially explicit MODIS data. The model generally captured the expected spatial and seasonal patterns of NEE as determined from measurements and the literature. Our study demonstrated that our empirical approach is effective for scaling up eddy flux NEE measurements to the continental scale and producing wall-to-wall NEE estimates across multiple biomes. Our estimates may provide an independent dataset from simulations with biogeochemical models and inverse modeling approaches for examining the spatiotemporal patterns of NEE and constraining terrestrial carbon budgets over large areas.; Organismic and Evolutionary Biology; Earth and Planetary Sciences; Engineering and Applied Sciences

‣ Desarrollo y evaluación de un software (MODQua) para el filtrado por calidad de productos MODIS: ¿Fenómenos reales o artificios del producto?

Perna, Pablo Alejandro; Carballo, Federico; Barraza Bernadas, Verónica Daniela; Grings, Francisco Matias; Bruscantini, Cintia Alicia
Fonte: Asociación Argentina de Ecología de Paisajes Publicador: Asociación Argentina de Ecología de Paisajes
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
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En este trabajo se presenta el software MODQua, teniendo como objetivo principal la evaluación de su capacidad en el análisis de los datos de calidad de MODIS. El instrumento MODIS (Moderate Resolution Imaging Spectroradiometer) ofrece numerosos productos que son muy utilizados en estudios ambientales. La información de calidad de dichos productos incluye la presencia de nubes, aerosoles, fiabilidad de la variable informada, entre otros. Globalmente, estos indicadores sirven para generar diferentes índices de calidad para una adquisición dada (Quality Assessment, QA). Sin embargo, dicha información esta brindada de forma no amigable para el usuario final (formato binario). Mediante la utilización de MODQua y el producto de NDVI del sistema Terra-MODIS (MOD13Q1), se realizó una evaluación de los errores asociados a las imágenes de NDVI según el distinto nivel de QA. Los resultados muestran que más de un 50% de pixeles presentaron baja calidad por presencia de nubes y/o contaminación atmosférica en las imágenes analizadas. Esto denota la necesidad de realizar un proceso de filtrado de los datos MODIS basados en los datos de QA, disminuyendo así las incertezas en el producto final. Para este fin el software MODQua ha resultado ser una herramienta de fácil utilización e interpretación de imágenes MODIS.; Fil: Perna...

‣ Análise espectro temporal de produtos do sensor MODIS como diagnóstico para a cafeicultura de precisão

Santos, Wesley Batista dos
Fonte: Universidade Federal de Lavras; Programa de Pós-Graduação em Engenharia Agrícola; UFLA; brasil; Departamento de Engenharia Publicador: Universidade Federal de Lavras; Programa de Pós-Graduação em Engenharia Agrícola; UFLA; brasil; Departamento de Engenharia
Tipo: Dissertação
Publicado em 23/11/2015 Português
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The coffee is an agricultural and economic activity of great importance for the Brazilian market. Despite the social and economic importance to the country, the coffee needs additional information from your production system. The remote sensing through satellite images and products available free, like MODIS sensor, can be a key tool for mapping and monitoring for the coffee. Therefore, the objective of this work was to analyze the application of MODIS sensor products as diagnostic data for precision coffee. The study area is located in the city of Campos Gerais/MG, Brazil with area of 461.28 hectares of coffee plantations, divided into experimental plots. Two times series were used and acquired from INPE, (a) time series EVI2 MODIS sensor; (b) number of rainfall (mm/month), the TRMM sensor. Another series used, acquired from NTSG, was to evapotranspiration (mm/month) of MOD16A2/A3 MODIS product and was also collected "in situ" property data in the study, such as, area, growing, productivity, among others. The collected data were selected and organized into a database. After creating the database, the spectral curves and performed correlation and regression for the variables (data) were generated. The results showed that EVI is influenced by moisture content and evapotranspiration...

‣ Estimation of Vegetation Water Content with MODIS data and Radiative Transfer Simulation

Zarco-Tejada, Pablo J.; Ustin, S. L.
Fonte: Conselho Superior de Investigações Científicas Publicador: Conselho Superior de Investigações Científicas
Tipo: Comunicación de congreso Formato: 56684 bytes; application/pdf
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In Proceedings of the First International Sysmposium on Recent Advances in Quantitative Remote Sensing, Valencia, Spain, 16-20 September, 2002; Radiative-transfer physically-based studies have previously demonstrated the relationship between leaf water content and leaf-level reflectance in the near-infrared spectral region. The successful scaling up of such methods to the canopy level requires modeling the effect of canopy structure and viewing geometry on reflectance bands and optical indices used for estimation of water content, such as NDWI and SRWI. This study conducts a radiative transfer simulation, linking leaf and canopy models, to study the effects of leaf structure, dry matter content, leaf area index, and the viewing geometry, on the estimation of leaf equivalent water thickness from canopy-level reflectance. The applicability of radiative transfer model inversion methods to MODIS is studied, investigating its spectral capability for water content estimation. A field sampling campaign was undertaken for analysis of leaf water content from leaf samples in 10 study sites of chaparral vegetation in California, USA, between March and June 2000. MODIS reflectance data were processed from the same period for equivalent water thickness estimation by model inversion linking the PROSPECT leaf model and SAILH canopy reflectance model. MODIS reflectance and viewing geometry values obtained from MOD09A1 product...

‣ Water content estimation in vegetation with MODIS reflectance data and model inversion methods

Zarco-Tejada, Pablo J.; Rueda, C. A.; Ustin, S. L.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 4085 bytes; image/gif
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Statistical and radiative-transfer physically based studies have previously demonstrated the relationship between leaf water content and leaf-level reflectance in the near-infrared spectral region. The successful scaling up of such methods to the canopy level requires modeling the effect of canopy structure and viewing geometry on reflectance bands and optical indices used for estimation of water content, such as normalized difference water index (NDWI), simple ratio water index (SRWI) and plant water index (PWI). This study conducts a radiative transfer simulation, linking leaf and canopy models, to study the effects of leaf structure, dry matter content, leaf area index (LAI), and the viewing geometry, on the estimation of leaf equivalent water thickness from canopy-level reflectance. The applicability of radiative transfer model inversion methods to MODIS is studied, investigating its spectral capability for water content estimation. A modeling study is conducted, simulating leaf and canopy MODIS-equivalent synthetic spectra with random input variables to test different inversion assumptions. A field sampling campaign to assess the investigated simulation methods was undertaken for analysis of leaf water content from leaf samples in 10 study sites of chaparral vegetation in California...

‣ Canopy water content estimates with AVIRIS imagery and MODIS reflectance products

Cheng, Yen-Ben; Riaño, D.; Zarco-Tejada, Pablo J.; Ustin, S. L.
Fonte: Society of Photo-Optical Instrumentation Engineers Publicador: Society of Photo-Optical Instrumentation Engineers
Tipo: Comunicación de congreso Formato: 4085 bytes; image/gif
Português
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En: Remote Sensing and Modeling of Ecosystems for Sustainability III . -- Proceedings of the International Society for Optical Engineering (SPIE), 14 August 2006 , San Diego, California, USA; We assessed the capability of AVIRIS and MODIS to estimate canopy water content. Hyperspectral water retrievals with AVIRIS data, EWT, were compared to in situ leaf water content and LAI measurements at a semi-arid site in southeastern Arizona. Retrievals of EWT showed good correlation with field canopy water content measurements. Statistical analysis also suggested that EWT was significant among seven different vegetation communities. Four MODIS indexes derived from band ratios using the reflectance product and were compared to retrievals of EWT with AVIRIS at both the semi-arid site and a temperate conifer forest. Good statistical agreements were found between AVIRIS EWT and all four MODIS indexes at the semi-arid site in savanna shrub communities. Slightly poorer correlations were found at the forest site where water indexes had better correlation to AVIRIS EWT than vegetation indexes. Temporal patterns of the four indexes in all semi-arid vegetation communities except creosote bush and agriculture show distinct seasonal variation and responded to precipitation at the savanna site. Three years of net ecosystem exchange (NEE) data from eddy covariance measurements at the forest site were compared to the time series of MODIS indexes. MODIS water indexes showed similar seasonal patterns to NEE that were strongest during the period of net carbon sequestration. In contrast...

‣ Evaluation of long-term NDVI time series derived from Landsat data through blending with MODIS data

Singh,D.
Fonte: Centro de Ciencias de la Atmósfera, UNAM Publicador: Centro de Ciencias de la Atmósfera, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 Português
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The aim of this study is to capitalize on the spatial detail of Landsat and the temporal regularity of MODIS acquisitions using a fusion approach (Spatial and Temporal Adaptive Reflectance Fusion Model, STARFM). Specifically, the 30 m Landsat-7 ETM+ (Enhanced Thematic Mapper plus) surface reflectance was predicted for a period of eight years (2002-2009) as the product of observed ETM+ and MODIS surface reflectance (MOD09Q1) on the predicted and observed ETM+ dates. A pixel based analysis for observed ETM+ dates covering winter and summer crop seasons showed that the prediction method was more accurate for NIR (mean r² = 0.87, p ≤ 0.01) compared to red band (mean r² = 0.65; p ≤ 0.01). The NDVI was computed from observed Landsat and predicted surface reflectance. The difference between NDVI from predicted and observed ETM+ data (prediction residual) was compared with the temporal residuals of NDVI from observed Landsat and MODIS data at two different dates. The prediction residuals for NDVI (spatial mean value of 0.0085) were found to be significantly lower than the temporal residuals (spatial mean value of 0.056 for MODIS and 0.051 for observed ETM+) implying that the prediction method was better than temporal pixel substitution. Investigating the trend in synthetic ETM+ NDVI values over a growing season revealed that phenological patterns were well captured. A direct comparison between the NDVI values obtained from MODIS and synthetic ETM+ images has shown a good consistency of the temporal dynamics but a systematic error that can be read as bias (MODIS NDVI over estimation). The relationship between synthetic ETM+ NDVI with observed precipitation and evaporation data was also studied and it was observed that monthly total precipitation and monthly evaporation of the preceding month have higher correlation coefficients (r² = 0.56 and r² = 0.59) with mean monthly synthetic ETM+ NDVI.