干旱区生态环境知识资源中心

The Penman-Monteith (FAO-56 PM) equation is suggested as the standard method for estimating evapotranspiration by the International Irrigation and Drainage Committee and the Food and Agriculture Organization of the United Nations (FAO). However, the major drawback of FAO-56 PM method is that air temperature, relative humidity, wind speed, and solar radiation are required which are not all available in many meteorological stations. In the present study, the 30 commonly used ET0 equations that belonged to 4 groups: (1) pan evaporation-based equations, (2) temperature-based equations, (3) radiation-based equations, and (4) mass transfer-based equations were evaluated against the FAO-56 PM equation as standard. In addition, 1 pan evaporation-based, 2 temperature-based, 4 radiation-based and 1 mass transfer-based equations for estimating ET0 were derived based on the FAO-56 PM method as a reference. The results showed that the mass transfer-based equations had the worst performances among the evapotranspiration equations evaluated. The ET0 values obtained from the equations, derived specifically for this location, were better than those estimated by existing equations.