Comparison of hourly and daily reference crop evapotranspiration equations across seasons and climate zones in Australia

Abstract

Estimates from the FAO Penman-Monteith (FAO-PM) and the standardized ASCE Penman-Monteith (ASCE-PM) hourly and daily reference evapotranspiration (ET0) equations were compared at daily scale, based on the hourly climate data collected from forty (40) geographically and climatologically diverse Automatic Weather Stations (AWS) across the Australian continent. These locations represent 23 agricultural irrigation areas in tropical, arid and temperate climates. The aims of this paper are to: compare the effects of different methods of estimating Clear-sky-radiation-(Rso); compare sum-of-hourly and daily ET0; compare the results of aggregation of hourly ET0 over 24h compared with daylight hours; ..