Estimation of mean reference evapotranspiration in Basrah City, South of Iraq using fuzzy logic

الملخص EN

Evapotranspiration (ET) is important for hydrological practices, water planning, and it plays an influential role in the design, operation and management of irrigation systems.

There are a number of methods suggested to estimate reference evapotranspiration (ETo).

Detailed meteorological data required for the equation of FAO-56 Penman-Monteith (P.M) method that was adopted by Food and Agriculture Organization (FAO) as a standard method in estimating reference evapotranspiration (ETo) are not often available, especially in developing countries.

In this research the possibility of estimating reference evapotranspiration using fuzzy logic control in BasrahCity is studied.

The four models of fuzzy logic are constructed based on the available meteorological data in BasrahCity during the period (1990-2012).Various combinations of long-term average monthly climatic data ofair temperature, relative humidity, wind speed and solar radiation are used as inputs to construct four models of fuzzy logic.

Fuzzy logic models evaluated based on root mean squared error (RMSE) and coefficient of correlation (R2).Depending on the values of RMSE and R2, model No.4 with input parameters (Tmean, Tmin, Tmax, Rh, Ws, Rn)give the best values of estimated (ETo), it gives a RMSE and Rvalues of 0.094 and 0.998 ,respectively.

Fuzzy logic models have high efficiency in estimating the reference evapotranspiration values