Application of the Surface Energy Balance Algorithm for Land (SEBAL) for spatial analysis of evapotranspiration in a commercial oil palm plantation in Jambi Province, Indonesia

摘要

Evapotranspiration (ET) is one of the climate elements which plays an important role in ecosystem water balance,including in oil palm plantations. Therefore, many mathematical equations and algorithms have been developed anddesigned to estimate and determine the spatial distribution of evapotranspiration. Remote sensing data are one of theimportant sources and techniques to estimate spatial variation of various climate elements, including ET. The mainobjective of this research is to estimate the spatial variation of ET using the SEBAL algorithm and Landsat-8 imagery ofa large-scale commercial oil palm plantation, i.e. PT Perkebunan Nusantara VI Batanghari, Jambi Province, Indonesia.The analysis is carried out using Landsat-8 (OLI/TIRS) data and reference meteorological data from a micrometeorologyflux tower. We calculated surface radiance, reflectance, albedo, Normalized Difference Vegetation Index (NDVI),emissivity, surface temperature, net radiation, soil heat flux, sensible heat flux, and latent heat flux to derive the hourlyand daily evapotranspiration from the study area. Validation of ET from the SEBAL model were performed against ETfrom aerodynamic measurements from a micrometeorological tower at the same site. Differences in ET within “only oilpalm cover” are relatively low and that difference in ET over the entire area of the oil palm plantation is mainly betweenoil palm vs. open lands, roads, and buildings. The evapotranspiration values of oil palm cover (NDVI 0.45-0.54) werebetween 2.42 ± 0.36 - 3.36 ± 0.17 mm d~(-1). There was no significant difference between ET derived from SEBALcompared to aerodynamic methods (p-value = 0.598; r = 0.75).