2007/05/01 by Nazzareno Diodato, Gianni Bellocchi · 1 citation
Environmental Science · Engineering · #Plant Water Relations and Carbon Dynamics #Hydrology and Watershed Management Studies #Water resources management and optimization
paper · doi:10.1029/2006wr005405
openalex publication_date 2007/05/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
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 (Δ T ), while REMCT replaces Δ 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) ≤ I ET ≤ 1 (worst). The REMCT estimates generally compared well with the FAO‐56 estimates (mean I ET = 0.029 against 0.187 and 0.255 with HS and DAHS, respectively). The three models performed similarly at low‐altitude sites. REMCT was superior at sites higher than 500 m above sea level, where the ET 0 − Δ T relationship was distorted (e.g., by an asymmetric lapse rate between maximum and minimum air temperatures).