ABSTRACT
This chapter is a condensation of a more detailed paper that Rick Allen and I prepared in 2000 [53] for the presentation at the Fourth National Irrigation Symposium, ASAE in Phoenix, Arizona. This chapter is also an edited version of my original paper that was prepared for a workshop on Evapotranspiration. This chapter emphasizes my involvement or association with my colleagues in the development and dissemination of new technology for estimating evapotranspiration [ET] in the United States of America [USA]. I reviewed current ET literature and older documents relating to the development of early evapotranspiration estimating methods in the USA. In this chapter, I have included some history of the development of the “ASCE Manual 70 Evapotranspiration and Water Requirements [54],” “FAO-56 Crop Evapotranspiration [4],” development of programs to calculate ET using satellite data [5, 9, 10], the new “ASCE Standardized Reference ET Equation [8],” a proposal for a one-step approach to estimate ET, and an update on the second edition of ASCE Manual 70. More detailed but less personnel-oriented, progress in measuring and modeling ET in agriculture can be found in a recent review article by Farahani et al. [34].
