Evaluation of the applicability of potential evapotranspiration models in Hungary

One of the most challenging problems in hydrometeorology is the quantification of potential evapotranspiration (PET) rates. The aim of this study was to identify PET models that can reliably approximate the FAO Penman– Monteith reference evapotranspiration or available PET data provided by the Hungarian Meteorological Service (HungaroMet) for Hungary while requiring fewer meteorological input variables. Nevertheless, an understanding of PET values and trends can offer invaluable insights into the drought sensitivity of an area. We analysed the performance of 18 PET models for Hungary based on meteorological data from 2010 to 2022 and identified and ranked the most relevant ones. The PET values were calculated at 16 meteorological stations using different models and subsequently ranked according to six distinct statistical indicators. As a basis for comparison, data from the nearest pan-evaporation measuring station and FAO Penman-Monteith (FAO-PM) values were calculated. PET provided by HungaroMet was used as the reference potential evaporation value. Model performances were ranked on a 1–120 scale. Our results showed that the temperature-based Oudin model had the most accurate performance, but in general, the radiation-based models were the most reliable. The spatial distribution of the data indicates that the performance of the PET models is somewhat inferior in the eastern and western regions of the country in comparison to that observed in the central areas. Our results are likely applicable to the temperate zone of similar subhumid climates.