Reference crop evapotranspiration estimated from geostationary satellite imagery

摘要

A revised Makkink formula is presented to estimate the Reference Crop Evapotranspiration (ET_o), as defined by the FAO, requiring incoming solar radiation and air temperature only, and allowing operational ET_o mapping with geostationary satellite (MSG) imagery. For 2008, daily MSG-ET_o compare well with "ground-truth" data collected over well-watered "FAO-grass". The project is carried out in the context of the LSF SAF project . It is argued that solar radiation must be preferred over measured net radiation as input variable for ET_o calculations.