Evaporation measurement and validation of meteorological models

Abstract

Identification of the best-fit meteorological model for evaporation measurement in a particular agroecological zone is a pre-requisite for cost-effective land management. A simulation experiment was conducted at Makerere University with the objective of determining the best-fit model for estimating evaporation. Meteorological data was collected from Makerere Meteorological Station and applied to different models to estimate potential evaporation. Actual evaporation from three mini lysimeters was used to validate models. Actual evaporation from the lysimeter varied between 2.6 to 6.73. mm day!. Results showed that measured actual evaporation was greater in the afternoon than in the mornings and varied significantly (P<0.05) over days. After a linear regression analysis of measured actual evaporation against estimates from meteorological models, models were ranked in the order of best fit as Priestley and Taylor, Makkink, Abtew, Hargreaves, Romanenko, Penman, Turc, CROPWAT, and Penman-Monteith.