Modelling of reference evapotranspiration using fuzzy logic rule based algorithm for sub-humid climate in mid-Himalayas.

摘要

Evapotranspiration is one of the major components of the hydrologic cycle and its accurate estimation is of paramount importance for many studies such as hydrologic water balance, design and management of irrigation system, and water resources planning and management. The FAO PenmanMonteith method has now been accepted as standard method to estimate reference evapotranspiration (ETo), but it requires several weather parameters. This study is an attempt to predict ETo using Fuzzy Logic Rule Based Algorithm (FLRBA) with minimum weather data set for Nagini watershed, located in Tehri Garhwal district (Uttarakhand), India. The ETo predicted by fuzzy logic rule based algorithm was found to be comparable with the ETo estimated by FAO Penman-Monteith method. The developed model was validated by testing its performance using correlation coefficient (R2=0.92), Root Mean Square Error (RMSE=0.51) and Coefficient of Variation of the Residual Error (CVRE=0.19). It manifests the applicability of developed fuzzy model to predict ETo for future events with lesser input variables.