Penman–Monteith Reference EvapotranspirationEstimation Models, Using Latitude–TemperatureData, in the State of Sinaloa, Mexico

The goal is to create regression models estimating the daily Penman-Monteith reference evapotranspiration (PM R ) using latitude-temperature for the state of Sinaloa. The reference evapotranspiration was calculated by the methods of Penman-Monteith using empirical equations (PM C ), Hargreaves (HA C ), and PM R . Prior to calculating PM C , the incident solar radiation (SR) was calculated. From the Acaponeta station (2005-2008, 2011-2013, and 2015-2017), all complete observed variables were obtained: mean temperature, incident solar radiation (SRg), average relative humidity, and average wind speed at a height of 10 m. The data from the eight weather stations were provided by the National Meteorological Service and the National Water Commission. The daily observed Penman-Monteith reference evapotranspiration (PM O ) was calculated. For validation, three simple linear regressions (SLR) were applied: SR vs SRg, PM C vs PM O, and PM R vs PM O hypothesis tests were applied to each SLR: Pearson correlation (Pr) vs critical Pearson correlation (Pcr). All rP were significantly different from zero (> |0.576|): SRg vs SR (Pr = 0.951), PM C vs PM O (Pr = 0.592), and PM R vs PM O (Pr = 0.625). This study provides new models that can motivate and support intelligent irrigation in "the breadbasket of Mexico.