It is a complex process, you need to develop all the equations, algorithms of SEBAL in order to obtain H and Rn. See Bastiaanssen, W.G.M., Menenti, M., Feddes, R.A. and Holtslag, A.A.M. (1998). A remote sensing surface energy balance algorithm for land (SEBAL), part 1: formulation. Journal of Hydrology, 212–213,
198 – 212.;
Mariotto I., et al., 2011. “Mapping evapotranspiration from ASTER data through GIS spatial integration of vegetation and terrain features”, PE&RS 77(5):483-493.
Hi Reza, that is even more challenging. Bill Kustas and Martha Anderson , U.S. Department of Agriculture, have written numerous papers on the calculation.
Could you share the information about the manuals of programming SEBAL in Python please. At this time I am working with SEBAL/METRIC model and I have some issues with the calculation of H.