Ref-ET 2.0

REF-ET is a compiled, stand-alone computer program that calculates reference evapotranspiration. Evapotranspiration (ET) is defined as the amount of water that evaporates from vegetation (transpiration) and from the underlying soil. Reference evapotranspiration is defined as the ET that occurs from a standardized "reference" crop such as clipped grass or alfalfa. Common usage in the United States and elsewhere has been to use the two reference crops of clipped grass (cool season varieties) and full-cover alfalfa (lucerne).