Closure to "History and Evaluation of Hargreaves Evapotranspiration Equation" by George H. Hargreaves and Richard G. Allen

The authors welcome the discussion by Samani on our paper and appreciate his cautionary statements regarding the assumption of constancy of KRS in the original Eq. (6), especially in humid or equatorial climates. Samani's findings, based on the prediction of monthly solar radiation from Knapp et al. (1980) using temperature range (TR) (daily maximum temperature minus daily minimum temperature), indicate the need for KRS larger than the 0.17 constant implicit to the original Eq. (8) when the TR is relatively small (less than about 7'C). It is worthwhile to note that in Samani's Fig. 1, KRS appears to only be statistically different from 0.17 in the 8-16 deg C range. TR does tend to be smaller in humid and subhumid climates than in semiarid and and climates.