Estimating Reference Crop Evapotranspiration in West Texas Under Limited Climate Data.

Crop reference evapotranspiration (ETo) can be estimated using complete and limited climate data. ASCE’s Standardized Reference Evapotranspiration Equation (ASCE-ET) and FAO Penman-Monteith equation (FAO-ET) use complete climate data whereas simple evapotranspiration models based on radiation and temperature use limited data. This study analyzed reference evapotranspiration at different stations of West Texas Mesonet using more comprehensive FAO Penman-Monteith equation and simple temperature based Hargreaves (HG) methods. The result showed that Hargreaves method underestimated ETo compared to FAO-ET. This study also derived new empirical parameters of Hargreaves equation using FAO-ET based reference evapotranspiration to improve HG equation in West Texas. Further study will analyze climate data from different weather networks of Texas to improve limited climate data based ETo equation for Texas.