Mapping of reference evapotranspiration using geostatistical analysis techniques

Three different interpolation methods (Inverse distance weighting, Ordinary kriging, Simple kriging) were comparatively analyzed to determine the spatial distribution of monthly reference evapotranspiration (ET_o) values calculated using the Hargreaves-Samani method (ET_o-HG) for ten districts of western Maharashtra. The spatial maps of monthly reference crop evapotranspiration were developed by using GIS interpolation techniques. Simple kriging interpolation technique was found suitable to map average reference crop evapotranspiration (ET_o) for all the months except February based on RMSE values. Spatial distribution maps can be used to derive location specific values of ET_o required for the estimation of crop water requirement.