Evaluation of the Penman-Monteith and other 34 reference evapotranspiration equations under limited data in a semiarid dry climate

摘要

Reference evapotranspiration (ETo) is an important parameter in hydrological, agricultural, and environmental studies. Accurate estimation of ETo helps to improve water management and increase water productivity and efficiency. While the Penman-Monteith ETo equation enjoys worldwide adoption as the most accurate ETo equation, the number of requested climatic variables makes its application very questionable under limited data conditions. The objective of this study was to evaluate the Penman-Monteith ETo equation under limited climatic data and 34 simple ETo equations that request few climatic variables. Five weather stations were considered under the semiarid and dry climate across New Mexico for the period of 2009-2017. The Penman-Monteith ETo equation showed good performance under missing solar radiation, relative humidity, and wind speed and could still be adapted under limited data conditions across New Mexico. However, it tended to underestimate daily ETo when more than one climatic variable data is missing. Among the simple ETo equations, four of the Valiantzas equations, along with the Makkink, Calibrated Hargreaves, Abtew, Jensen-Haise, and Caprio equations, were the best performing ones compared to the Penman-Monteith equation and could be the best alternative ETo estimation methods. These alternative equations could be used by irrigation managers, producers, engineers, and university researchers to improve water management across the dry semiarid and arid zone across New Mexico, as well as other semiarid areas where water is the most limiting factor to food and fiber production.