Comparison of the Monthly Values of Potential Evapotranspiration Estimated through Different Methods

From the period of 1981-2012 the present daily weather data of 32 yrs have been used for the analysis of PET of monthly and annual basis. Average monthly values of PET computed by different methods in Ambikapur station shows that the Thornthwaite PET values are overestimated during summer and mansoon months and underestimated during winter months. The annual PET values computed by all methods are higher at Raipur and lower at Jagdalpur. All the PET computed by different methods are overestimated as comparison to Pan evaporation data. Modified penman values are higher at Raipur while Hergreaves method PET values are highest at Jagdalpur and Ambikapur. In seasonal PET based on monthly PET values, the total PET during Kharif and rabi seasons were examined at different stations. The total values of PET during kharif season by different methods varied from 515 mm to 877 mm at Raipur while the varied from 598 to 747 at ambikapur and the same values computed by different methods varied from 384 to 709 at jagdalpur.