An Evapotranspiration Algorithm in a Dryland Irrigation System: A Case Study in Coleambally, NSW, Australia

Abstract

This research expands on the continuous collection of ground truth data to feed in various empirical relationships enabling the calibration of a simple two source energy balance in order to provide with instantaneous remote sensing based ET in an irrigated area of Murray Darling Basin under Australian conditions. Standard satellite remote sensing Terra MODIS products such as NDVI, LST or Albedo correlations to ground truth through scales differences are explored for Coleambally Irrigation Area where extensive field campaigns have been carried out over two years. The sensible heat flux (the energy used for air convection) and evaporative fraction results estimated from a two source energy balance approach has been calibrated with Eddy Covariance Flux Tower installed at the experimental farm where maize crop was grown. Additionally, an input parameters sensitivity analysis has been carried out by replacing flux tower data with semi-empirical data derived from crop calendar and Terra MODIS products.