Calibração do Sebal/Metric e mapeamento do saldo de radiação com imagens Landsat 5 – Tm e modelo de elevação digital.

Abstract

The intense application of the SEBAL / METRIC algorithm for determination of the energy balance components at surface requires the calibration of some equations to get better precision of their estimates. In that sense, the study proposed the calibration and mapping of the radiation balance by applying SEBAL / METRIC to Landsat 5 – TM images, in two atmospheres with different characteristics: a humid sub-tropical and semi-arid climates both in Brazil, corresponding respectively to Mogi Guaçu - SP and Low Jaguaribe - CE basins. For the calibration process the methods of linear regression and the one of attempt-mistake based on the selection of the results in function of the medium error, absolute medium error and in the relationship among these were used. In the mapping of the radiation balance five TM – Landsat 5 images for Mogi Guaçu basin and three for the Baixo Jaguaribe basin were used. The data used in the validation process were collected in three micrometeorological stations, being two installed in Mogi Guaçu basin (one in Cerrado Bioma and other one in sugarcane crop) and in Low Jaguaribe basin (irrigated banana crop). The results obtained in the calibration process were considered very satisfactory, with estimates values of net radiation close to the observed data, promoting significant improvement and success to the proposed objective. In the mapping of net radiation on the two studied atmospheres, eventual variation of this component was detected on Mogi Guaçu's basin along the analyzed period, with results that corroborate with the literature.