Estimation of actual evapotranspiration using remote sensing data

摘要

Estimation of actual evapotranspiration (AET) and its spatial distribution are important to understandingudof catchment hydrology. The AET is driven by net energy available to evaporate water from soil and vegetationudsurfaces, and to transpirate water from vegetation. However, estimating AET is difficult as the evapotranspirationudprocess involves complex physical and biological processes. It is further complicated when there is lack of measuredudmeteorological variables data which are required for estimation. These data are essential to quantify the availabilityudof net energy and the aerodynamic effects of the evapotranspiration process. Remote sensing (RS) data, which areudwidely available and easily accessible than the measured ground data, can be used to estimate the availability of netudenergy for AET. However, still some measured ground data are required to quantify the aerodynamic effects onudAET. In this study, remote sensing data and readily available climate datasets were used as inputs to an energyudbalance technique to estimate AET, as an alternative to the traditional ET estimation procedures, which requireudmeasured hydrometeorological data. The Macalister subcatchment in the Thomson catchment in Victoria (Australia)udwas used as the case study considering the study period from January 2003 to December 2008.