Evapotranspiration of banana using the SEBAL algorithm in an irrigated perimeter from the Northeastern Brazil

ABSTRACT The study aimed to estimate the evapotranspiration of banana (Musa spp.) in an irrigated perimeter of the municipality of Barbalha, CE, Brazil, using the Surface Energy Balance Algorithm for Land (SEBAL) model and to compare these results with those estimated using the Penman-Monteith method. Landsat-8 OLI/TIRS satellite images of May 22, 2016, August 10, 2016, and October 29, 2016 and data on temperature, relative humidity, wind speed and solar irradiance, obtained from an automatic weather station, installed close to the experimental area were used. The bands were stacked, and the stacked images were cut, then mathematical operations and evapotranspiration estimation were performed, whose actual daily banana values, estimated by the SEBAL algorithm, were 4.70; 5.00 and 6.50 mm, respectively, for May 22, August 10, and October 29, 2016. Comparing the daily ETr given by SEBAL with that obtained by the Penman-Monteith method, absolute errors of 0.26, 0.44, and 0.64 mm d-1 were observed for May 22, August 10, and October 29, 2016, respectively. These errors are within the ranges accepted in the literature.摘要 本研究旨在借助地表能量平衡算法（Surface Energy Balance Algorithm for Land，SEBAL），估算巴西塞阿拉州巴尔巴利亚市灌溉区域内芭蕉属（Musa spp.）香蕉的蒸散发，并将该估算结果与彭曼-蒙特斯（Penman-Monteith）方法得到的结果进行对比。本研究采用了2016年5月22日、8月10日及10月29日的Landsat-8 OLI/TIRS卫星影像，以及安装于试验区域附近的自动气象站获取的气温、相对湿度、风速与太阳辐射数据。对影像波段进行拼接与裁剪后，开展数学运算与蒸散发估算。经SEBAL算法估算得到的香蕉实际日蒸散发量，在2016年5月22日、8月10日、10月29日分别为4.70 mm、5.00 mm与6.50 mm。将SEBAL得到的实际日蒸散发（ETr）与彭曼-蒙特斯方法的估算结果对比后发现，2016年5月22日、8月10日、10月29日的绝对误差分别为0.26、0.44与0.64 mm·d⁻¹，上述误差均处于学界公认的合理区间内。