Simplified modeling of downwelling long-wave radiation over brazilian semi-arid under irrigation conditions

Abstract

Data collected in a micrometeorological campaign conducted in a banana orchard in a semi-arid land of Brazil in the period from 2005 to 2006 were used
for a long-wave radiation (LWR) study. The objective of the study was the calibration and determination of a long-wave radiation models. In this sense, two established
models were used for estimating apparent emissivity of the atmosphere locally calibrated. The percentage and root square errors obtained by calibrated equations were
equal to 3.28% and 16.10 Wm-2 for the model of Brutsaert and 2.46% and 12.68 Wm-2 for the model Bastiaanssen. It was found that the errors obtained with the
calibrations performed substantially decreased and that estimates of the radiation incident wave with the same produce results far more accurate than those made with
the calibrations proposed originally. This shows the variability of the coefficients in the regions studied and the importance of local calibration.