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| Registros recuperados: 289 | |
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| Filgueiras,Roberto; Mantovani,Everardo C.; Althoff,Daniel; Dias,Santos H. B.; Cunha,Fernando F. da. |
| ABSTRACT Surface temperature (Ts) is a determining factor to obtain energy balance parameters, being relevant to understand the influence of this variable on the estimation of evapotranspiration. Thus, the objective of this study was to simulate errors in Ts estimation to verify the consequences of actual evapotranspiration (ETa) estimated by the SAFER (Simple Algorithm for Evapotranspiration Retrieving) model. For this, an image of the Landsat-8 satellite was used to induce errors from 0.2K to 10K in the variable Ts, allowing verifying the consequences in the ETa data. After the estimations of Ts and ETa, the quantitative consequences and dynamics of Ts impact on the ETa data were verified along the different land uses in the study area. The results... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Energy balance; Irrigated areas; Remote sensing; NDVI. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000800023 |
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| Beneduzzi,Humberto M.; Souza,Eduardo G.; Bazzi,Claudio L.; Schenatto,Kelyn. |
| ABSTRACT: Optimization of N management is one of the great challenges to be overcome in grain production, as it is directly related to productivity and can also cause environmental damage. Precision agriculture aims to solve this problem by applying nitrogen fertilizer at varying rates. Reflectance sensors are instruments capable of estimating N needs in various crops, including grain crops. However, it is not clear how these sensors perform under varying solar radiation and cloud cover, due to a lack of research on their temporal variability. Thus, this study examined the temporal variability of the NDVI (normalized difference vegetation index), as measured by an active reflectance sensor, in both soybean and wheat crops. The NDVI data were collected... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Precision agriculture; Remote sensing; Vegetation index; NDVI. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162017000400771 |
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| Rolim,João; Navarro,Ana; Vilar,Pedro; Saraiva,Cátia; Catalao,Joao. |
| ABSTRACT Accurate crop data are essential for reliable irrigation water requirements (IWR) calculations, which can be acquired during the crop growth season for a given region using earth observation (EO) satellite time series. In addition, a relationship between crop coefficients and the NDVI can be established to allow for crop evapotranspiration estimation. The main objective of the present work was to develop a methodology, and its implementation in an application software, to extract crop parameters from EO image time series for a set of parcels of different types of crops, to be used as input data for a soil water balance model to compute IWR. The methodology was tested at two distinct test sites, the Vila Franca de Xira (site I) and Vila Velha de... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Remote sensing; Irrigation; Software; NDVI; Crop phenology; Crop coefficient. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000300380 |
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| Carvalho,Daniel C. De; Pessoa,Mayara M. De L.; Pereira,Marcos G.; Delgado,Rafael C.. |
| ABSTRACT This study aimed to assess vegetal cover evolution on a river island within the Ecological Station of (EEP), by remote sensing. For this purpose, Normalized Difference Vegetation Indexes were generated for Landsat 1 (1973) and Landsat 5 (1984, 1990, 2000 and 2011) images. Five landscape units were identified in the field: bare soil, Rough savanna, Typical savanna, Forested savanna and Evergreen dry woods. Only Forested savanna and Evergreen dry woods showed poor spectral splitting, being thus considered as a forestry complex. Changes throughout time have occurred in all units, with decreasing in bare soil areas (-2.56 ha year−1), Rough savanna (-0.66 ha year−1) and Typical savanna (-0.94 ha year−1) and with an increase in the Forested savanna... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Remote sensing; Environmental monitoring; Vegetation index. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000601186 |
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| Junges,Amanda H.; Fontana,Denise C.; Pinto,Daniele G.. |
| This study aimed to propose methods to identify croplands cultivated with winter cereals in the northern region of Rio Grande do Sul State, Brazil. Thus, temporal profiles of Normalized Difference Vegetation Index (NDVI) from MODIS sensor, from April to December of the 2000 to 2008, were analyzed. Firstly, crop masks were elaborated by subtracting the minimum NDVI image (April to May) from the maximum NDVI image (June to October). Then, an unsupervised classification of NDVI images was carried out (Isodata), considering the crop mask areas. According to the results, crop masks allowed the identification of pixels with greatest green biomass variation. This variation might be associated or not with winter cereals areas established to grain production. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Wheat; Black oat; Remote sensing; MODIS; NDVI. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162013000400027 |
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| Araújo,Gleyce K. D.; Rocha,Jansle V.; Lamparelli,Rubens A. C.; Rocha,Agmon M.. |
| The search for low subjectivity area estimates has increased the use of remote sensing for agricultural monitoring and crop yield prediction, leading to more flexibility in data acquisition and lower costs comparing to traditional methods such as census and surveys. Low spatial resolution satellite images with higher frequency in image acquisition have shown to be adequate for cropland mapping and monitoring in large areas. The main goal of this study was to map the Summer crops in the State of Paraná, Brazil, using 10-day composition of NDVI SPOT Vegetation data for 2005/2006, 2006/2007 and 2007/2008 cropping seasons. For this, a supervised digital classification method with Parallelepiped algorithm in multitemporal RGB image composites was used, in order... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Remote sensing; Time series; Crop yield estimates. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162011000400014 |
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| Ferreira,Elizabeth; Toledo,Joice H. de; Dantas,Antonio A. A.; Pereira,Rafael M.. |
| Medium-resolution satellite images have been widely used for the identification and quantification of irrigated areas by center pivot. These areas, which present predominantly circular forms, can be easily identified by visual analyses of these images. In addition to identifying and quantifying areas irrigated by center pivot, other information that is associated to these areas is fundamental for producing cadastral maps. The goal of this work was to generate cadastral mapping of areas irrigated by center pivots in the State of Minas Gerais, Brazil, with the purpose of supplying information on irrigated agriculture. Using the satellite CBERS2B/CCD, images were used to identify and quantify irrigated areas and then associate these areas with a database... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Irrigated agriculture; Remote sensing; Geographic information system (GIS); Image visual interpretation. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162011000400015 |
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| Gusso,Aníbal; Ducati,Jorge Ricardo; Cotlier,Carlos G; Lopez,Diego A. G. |
| A search is made for indicators of the presence of phytoplankton, using satellite images of the Pacific (Central Chile) and Atlantic (South Brazil). AVHRR/NOAA-16 and -17 visible (1 and 2) and thermal (4 and 5) channels were used to perform a detection test, respectively, the Suspended Particulate Matter (SPM) and the Sea Surface Temperature (SST). In Brazilian waters, a positive correlation is found between SST and SPM's reflectance. This is interpreted as due to phytoplankton being more abundant in colder waters, where nutrients availability are higher because CO2 dissolution rates, thus being a favorable environment for phytoplankton contents, which when mixed with SPM, tends to reduce the total water reflectance, since organic matter causes absorption... |
| Tipo: Journal article |
Palavras-chave: Phytoplankton biomass; Remote sensing; AVHRR/NOAA. |
| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382004000200046 |
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| Yáñez,E.; Silva,C.; Nieto,K.; Barbieri,M.A.; Martínez,G.. |
| A work of gathering historical fishing (catch, fishing effort, CPUE, characteristics and operation of purseiner fleet) and satellite (NOAA, SeaStar and SeaWind) database of northern Chile, and fishing and oceanographic in situ sampling for validation purpose is made. With this information and the use of geographical information system (GIS) the distribution of pelagic resources and the associated environmental conditions (sea surface temperature, thermal gradients, chlorophyll concentration and wind fields) are analysed in order to develop a probable fishing ground (PFG) index prediction model. A PFG model of anchovy (Engraulins ringens) is operative for the northern Chile. The impact of the use of PFG charts was evaluated analyzing the operational... |
| Tipo: Journal article |
Palavras-chave: Pelagic fisheries; Northern Chile; Remote sensing; GIS; PFG index and model. |
| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382004000300048 |
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| Суслин, В. В.; Чурилова, Т. Я.; Сосик, Х. М.. |
| Анализ стандартных спутниковых продуктов SeaWiFS второго уровня, характеризующих выходящее из-под поверхности воды излучение nLw(λ) в спектральных каналах (СК) λ = 490, 510 и 555 нм, показал, что их комбинация в виде индексов, определяемых как отношения I510 = nLw(555)/nLw(510) и I510 = nLw(510)/nLw(490), обладает в Чёрном море существенной нелинейностью в течение года. Эта особенность легла в основу метода разделения вкладов пигментов фитопланктона aph(λ) и суммы детрита и жёлтого вещества aCDM(λ) в поглощение света морской водой, и, как следствие, предложен региональный алгоритм определения концентрации хлорофилла а (Ca). Показано, что существуют, как минимум, два типа решений, соответствующих различному характеру поглощения света черноморской водой в... |
| Tipo: Journal Contribution |
Palavras-chave: Видимый диапазон; Дистанционное зондирование; Поглощение; Хлорофилл а; Окрашенное растворённое органическое вещество; Цианобактерии; SeaWiFS; Региональный алгоритм; Чёрное море; Visible domain; Remote sensing; Absorption; Chlorophyll a; Colored dissolved organic matter; Cyanobacteria; Regional algorithm; Black Sea; Видимий діапазон; Дистанційне зондування; Поглинання; Хлорофіл а; Забарвлена розчинена органічна речовина; Ціанобактерії; Регіональний алгоритм; Чорне море. |
| Ano: 2008 |
URL: http://repository.ibss.org.ua/dspace/handle/99011/808 |
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| SANO, E. E.; BEZERRA, H. da S.; BARCELLOS, A. de O.; ROSA, R.. |
| RESUMO: Desde o início da década de 1970, o Bioma Cerrado vem sendo intensamente ocupado para a produção de carne bovina. Segundo dados do Censo Agropecuário do IBGE de 1995/1996, nesse ecossistema, existem 49,5 milhões de hectares de pastagens cultivadas concentradas nos Estados de Goiás (14.150.900 hectares), Mato Grosso do Sul (11.970.463 hectares) e Mato Grosso (8.884.790 hectares). A maioria das pastagens cultivadas do Cerrado vem apresentando níveis alarmantes de degradação, requerendo a implementação de um programa racional e economicamente viável de recuperação. Visando a fornecer subsídios para um programa dessa natureza,nesse estudo, avaliou-se a possibilidade de identificar os principais tipos de pastagens cultivadas do Cerrado e os seus... |
| Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E) |
Palavras-chave: Degradação; Feed grasses.; Cerrado; Gramínea Forrageira; Pastagem Cultivada; Pastagem; Sensoriamento Remoto.; Degradation; Remote sensing; Pastures; Sown pastures.. |
| Ano: 2002 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/559112 |
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| INAMASU, R. Y.; BERNARDI, A. C. de C.; VAZ, C. M. P.; NAIME, J. de M.; QUEIROS, L. R.; RESENDE, A. V. de; VILELA, M. de F.; JORGE, L. A. de C.; BASSOI, L. H.; PEREZ, N. B.; FRAGALLE, E. P.. |
| O início da agricultura de precisão (AP) teve foco em máquinas dotadas de receptores GPS (Global Positioning System) e mapas de produtividade. Talvez, devido à essa fase, estabeleceu-se no Brasil, um senso comum de que o tema AP é uma área do conhecimento relacionada à sofisticação das máquinas agrícolas por meio de eletrônicas embarcadas e sistemas computacionais complexos, apesar do impacto final objetivar a sustentabilidade do agronegócio. A comunidade acadêmica, por sua vez, priorizou trabalhos iniciais voltados ao desenvolvimento de máquinas e equipamentos, por entender que ali estavam os principais desafios. |
| Tipo: Capítulo em livro técnico (INFOTECA-E) |
Palavras-chave: Agricultura de Precisão; Sensoriamento Remoto; Precision agriculture; Remote sensing. |
| Ano: 2011 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/908112 |
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| Registros recuperados: 289 | |
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