66 resultados para Essa (Meteorological satellite)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The best irrigation management depends on accurate estimation of reference evapotranspiration (ET0) and then selection of the appropriate crop coefficient for each phenological stage. However, the evaluation of water productivity on a large scale can be done by using actual evapotranspiration (ETa), determined by coupling agrometeorological and remote sensing data. This paper describes methodologies used for estimating ETa for 20 centerpivots using three different approaches: the traditional FAO crop coefficient (K-c) method and two remote sensing algorithms, one called SEBAL and other named TEIXEIRA. The methods were applied to one Landsat 5 Thematic Mapper image acquired in July 2010 over the Northwest portion of the Sao Paulo State, Brazil. The corn, bean and sugar cane crops are grown under center pivot sprinkler irrigation. ET0 was calculated by the Penman-Monteith method with data from one automated weather station close to the study site. The results showed that for the crops at effective full cover, SEBAL and TEIXEIRA's methods agreed well comparing with the traditional method. However, both remote sensing methods overestimated ETa according to the degree of exposed soil, with the TEIXEIRA method presenting closer ETa values with those resulted from the traditional FAO K-c method. This study showed that remote sensing algorithms can be useful tools for monitoring and establishing realistic K-c values to further determine ETa on a large scale. However, several images during the growing seasons must be used to establish the necessary adjustments to the traditional FAO crop coefficient method.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Ciência Florestal - FCA
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The objective of this work was to evaluate the sediment production in the initial part of the Pardo River Basin - Botucatu/SP from 1994 to 1999, using the mathematical hydrological model SWAT. It was used topographic maps and satellite data manipulated in GIS using the software SPRING 5.1.6. The simulation of sediment production was generated with the aid of an interface between the hydrological model SWAT 2009 with ArcView ®, version 9.3. The maps of Soil, Land Use and Digital Elevation Model (DEM) were generated in the GIS-SPRING 5.1.6 and exported to ArcSWAT 2009. The tabular data related to the parameters of soil and meteorological parameters were entered directly to the SWAT. The model allowed to estimate the sediment production. A sediment average production rate of 33.866 ton ha-1 over the six years of study was computed in the point of discharge of the basin.