Evaluation of nine reference evapotranspiration models in Traghen region, Southwest of Libya


  • Ali Othman Alghusni Department of Soil and water, Faculty of Agriculture, Omar Al-Mukhtar University, El-Beida, Libya.




reference evapotranspiration, FAO Penman-Monteith, FAO Radiation, FAO Blaney-Criddle, Turc, Kharrufa


  This research was carried out to evaluate nine reference evapotranspiration, and find out an alternative models to the standard FAO Penman-Monteith model in Traghen region southwest of Libya. The models applied were standard FAO Penman-Monteith, FAO Radiation, FAO Blaney-Criddle, Hargreaves-Samani, Priestley-Taylor, Makkink, Turc, Thornthwaite, Kharrufa and McCloud.  The models were compared with the FAO Penman-Monteith model using root mean square error (RMSE) , mean bias error (MBE), Pearson type goodness of fit index (R2), refined index of agreement (dr), modeling efficiency (Ef) and t-test.  Results showed that FAO Radiation and FAO Blaney-Criddle models overestimated ETo by values ranged from 0.64% to 16.06%.  However, Kharrufa and McCloud models overestimated ETo in some months and underestimated ETo in some other months.  Whereas, the other models underestimated ETo by values ranged from -86.69 % to -6.02%.  The FAO radiation model gave the highest dr (0.892) and Ef (0.951) values, and the lowest RMSE (0.534 mm/day), indicating that this model was the best alternative to the FAO Penman-Monteith model in the study region, followed by FAO Blaney-Criddle model with dr value of 0.851, Ef value of 0.878, and RMSE value of 0.845 mm/day.  In addition, FAO radiation model showed the second best R2 and MBE values at 0.993 and 0.473, respectively  Also, FAO Blaney-Criddle model showed the third best R2 value at 0.989.  Therefore, FAO radiation model is ranked the first and FAO Blaney-Criddle model is ranked the second.  According to the statistical measures stated above, Turc model ranked the third, Kharrufa model ranked forth.  Models of Hargreaves-Samani, Makkink, Priestley-Taylor, McCloud and Thornthwaite ranked fifth, sixth, seventh, eighth and ninth, respectively.  T-test analysis at 5% level of significance indicated that there is a significant difference between the FAO Penman-Monteith model and all models except Kharrufa and McCloud models.


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How to Cite

Alghusni, A. O. . (2020). Evaluation of nine reference evapotranspiration models in Traghen region, Southwest of Libya. Al-Mukhtar Journal of Sciences, 35(3), 225–246. https://doi.org/10.54172/mjsc.v35i3.299



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