Application of new mass transfer formulae for computation of evapotranspiration

Abstract

This study aims to compare mass transfer-based models to detect the best model under different weather conditions. For this purpose, weather data were gathered from 181 synoptic stations in 31 provinces of Iran. The reference crop evapotranspiration was estimated using 11 mass transfer-based models and was compared with the FAO Penman–Monteith model. The results showed that the Penman model estimates the reference crop evapotranspiration better than other models in the most provinces of Iran. However, the values of R² were less than 0.90 for 24 provinces of Iran. Therefore, the models were calibrated using new formulae and preciseness of estimation was increased. The mass transfer-based models estimated the reference crop evapotranspiration in the eastern provinces (desert regions) of Iran better than other provinces. The best values of R² were 0.96 and 1.00 for Trabert and Penman models in AR and TE, KE, and YA provinces before and after calibration, respectively.

Keywords:

• calibration
• evapotranspiration
• FAO Penman–Monteith
• humidity
• Iran
• mass transfer

Notes on contributors

Mohammad Valipour is a Ph.D. candidate in Agricultural Engineering-Irrigation and Drainage at Sari Agricultural Sciences and Natural Resources University, Sari, Iran. He completed his B.Sc. Agricultural Engineering-Irrigation at Razi University, Kermanshah, Iran in 2006 and M.Sc. in Agricultural Engineering-Irrigation and Drainage at University of Tehran, Tehran, Iran in 2008. Number of his publications is more than 50. His current research interests are surface and pressurized irrigation, drainage engineering, relationship between energy and environment, agricultural water management, mathematical and computer modeling and optimization, water resources, hydrology, hydrogeology, hydroclimatology, hydrometeorology, hydroinformatics, hydrodynamics, hydraulics, fluid mechanics, and heat transfer in soil media.