Modeling reference evapotranspiration over complex terrains from minimum climatological data

This work presents methods where monthly based climate data are used to estimate reference evapotranspiration (ET(0)). The objective was to evaluate two monthly ET(0) models (Hargreaves-Samani, HS; Droogers-Allen HS, DAHS) and compare the results with an improved model (reference evapotranspiration model for complex terrains, REMCT). HS and DAHS are both based on the monthly temperature range (delta)(T), while REMCT replaces (delta)T with a monthly adjusted function (reference minimum air temperature). The test area was peninsular-insular Italy, where 13 stations with sufficient data to calculate FAO-56 Penman-Monteith ET(0) were available. The three models were evaluated against FAO-56 over a validation data set of six stations, using a multiple-statistics indicator: 0 (best)