A preliminary evaluation of the ‘simplified triangle’ with Sentinel-3 images for mapping surface soil moisture and evaporative fluxes

Abstract This study provides the first results from an initial exploration of the so-called ‘simplified triangle’ for estimating evaporative fraction (EF) and surface soil moisture (SSM) from remotely sensed data of land surface temperature (Ts) and a vegetation index (VI) derived from ESA's Sentinel-3 satellite. The technique is implemented for 11 cloud-free days of year 2018 in a typical savannah Mediterranean site located in Spain, which is part of the CarboEurope ground observational network. In overall, the preliminary results obtained demonstrated the potential of the technique in mapping both EF and SSM. A Root Mean Square Error (RMSE) of 0.063 and 0.048 vol vol−1 and correlation coefficient (R) of 0.777 and 0.439 for EF and SSM, respectively, were reported. Results are of considerable scientific and practical value in regards to the evaluation of the potential of the examined technique for deriving key biophysical parameters of the Earth's system.