abstract = "The reference evapotranspiration (ETo) is an essential
component in hydrological and ecological processes. The
objective of this research is to develop an explicit
model to estimate ETo only using commonly measurable
meteorological parameters such as relative humidity,
air temperature, and wind speed, where the measurements
corresponding to solar radiation are omitted. The model
was generated using Genetic Programming (GP),
evaluated, and validated with reference data ETo using
FAO56-PM. This reference data was obtained from
different climates (warm-temperate and arid-warm) and
latitudes, acquired from CIMIS stations in the state of
California, United States, and the El Porvenir station
in the state of Coahuila, in north-central Mexico. a
total of 3754 results were generated, demonstrating a
significant improvement in the estimation of ETo
compared to the Hargreaves Samani model. our approach
outperformed the Hargreaves-Samani model in the testing
phase by 16%...",