Global scale monthly Priestley-Taylor (PT) coefficients for reference evapotranspiration (ETo) estimation

Published: 27 February 2023| Version 1 | DOI: 10.17632/hnnddrbfbj.1


The Priestley-Taylor (PT) method is widely used in hydrologic and crop models to estimate reference evapotranspiration (ETo) or atmospheric demand for water. However, the default value of the PT coefficient (PTa=1.26) cannot assure reliability under different climatic regions. Here, we provide monthly PTa values at global scales with a spatial resolution of 0.25° using weather data from the daily Princeton Global Forcing dataset (0.25° × 0.25°, 1948-2016). The PTa values was calculated using an analytical expression for PT coefficient following the FAO-PM method. The data generated from this study can be directly incorporated into hydrologic and crop models using the PT method. Details can be found in our paper: Su, Q., and Singh, V.P. (2023). Calibration-free Priestley-Taylor Method for Reference Evapotranspiration Estimation, Water Resources Research, e2022WR033198,



Clemson University


Hydrology, Evapotranspiration, Agricultural Irrigation, Irrigation, Agricultural Hydrology