A Comparative Study for Estimating Reference Evapotranspiration Models over Kano, Nigeria

Abstract

The major factor faced by Agricultural activities is water scarcity. Water is very essential in Agricultural activities (plantation), crop acquires water naturally by precipitation and subsurface moisture, when the supply of water is inadequate for crop use, mostly results to irrigation. This present study estimates and compares six various universally accepted models for estimating reference evapotranspiration (ET0) for Kano situated in the Sahelian climatic zone of Nigeria using measured meteorological parameters of monthly average daily global solar radiation, sunshine hour, wind speed, minimum and maximum temperatures and relative humidity covering a period of thirty one years (1988 – 2018). Four different statistical validation indices of Root Mean Square Error (RMSE), Mean Bias Error (MBE), Mean Absolute Error (MAE) and coefficient of correlation (R) were carried out to test the accuracy of the evaluated models. The result indicated that high value of ETo was found in the month of April with 10.0256 mm/day for Kano and a low value was found to be in August with 5.0804 mm/day for Kano. The Blaney – Morin Nigeria model was found more accurate for Kano with RMSE, MBE, MAE and R values as 1.5078 mm/day, -1.4634 mm/day, 1.4634 mm/day and 0.9790 respectively.