The Surface Energy Balance System (SEBS) is proposed to estimate atmospheric turbulent fluxes and evaporative fraction using satellite earth observation data combined with meteorological information. SEBS consists of tools for determining land surface parameters, a model for calculating the roughness length for heat transfer, and a new formulation for estimating the evaporative fraction based on energy balance at limiting cases. Four experimental datasets are used to assess SEBS, demonstrating its capability to estimate turbulent heat fluxes and evaporative fraction with acceptable accuracy. The uncertainties in estimated heat fluxes are comparable to those in in-situ measurements. SEBS is validated using field datasets from cotton, shrub, grass, and remote sensing data from the EFEDA campaign, showing good agreement with measured values. Error analysis indicates that the mean error of SEBS estimates is around 20% relative to the mean sensible heat flux, with uncertainties in roughness height for heat transfer being significant. The study concludes that SEBS is a credible and independent approach for estimating turbulent heat fluxes and evaporative fraction, with potential applications in hydrological, atmospheric, and ecological modeling.The Surface Energy Balance System (SEBS) is proposed to estimate atmospheric turbulent fluxes and evaporative fraction using satellite earth observation data combined with meteorological information. SEBS consists of tools for determining land surface parameters, a model for calculating the roughness length for heat transfer, and a new formulation for estimating the evaporative fraction based on energy balance at limiting cases. Four experimental datasets are used to assess SEBS, demonstrating its capability to estimate turbulent heat fluxes and evaporative fraction with acceptable accuracy. The uncertainties in estimated heat fluxes are comparable to those in in-situ measurements. SEBS is validated using field datasets from cotton, shrub, grass, and remote sensing data from the EFEDA campaign, showing good agreement with measured values. Error analysis indicates that the mean error of SEBS estimates is around 20% relative to the mean sensible heat flux, with uncertainties in roughness height for heat transfer being significant. The study concludes that SEBS is a credible and independent approach for estimating turbulent heat fluxes and evaporative fraction, with potential applications in hydrological, atmospheric, and ecological modeling.