Comprision study on mapping of ET in the CIA of Murrumbidgee catchment with remote sensed satellite data: Examples from National Airborne Field Experimentation

This study focused on actual Evapotranspiration (ET) characterization in Coleambally Irrigation Area (CIA), Murrumbidgee Irrigation Area (MIA) and its ambient region using the SEBAL model with remotely sensed TERRA/MODIS, NOAA/AVHRR and Landsat-5 TM data in the Area Of Interest (AOI) for the National Airborne Field Experimentation (NAFE06) campaign in 2006. Results showed that actual ET estimated from NOAA AVHRR 18 was always overestimating as comparison to Eddy system (on average 38%) during the image acquisition dates. However, for the same image acquisition dates, TERRA/MODIS ET ranges from 3.7% lower to 21.7% higher than the Eddy system. Landsat 5 TM modeled ET results were comparable to the Eddy Covariance system having a minor error with an average of 4.09%. It was proven possible to simultaneously use SEBAL for different sensors with the combination of high spatial and temporal resolution to estimate ET spatial distribution characteristics though the accuracy of NOAA-AVHRR derived result is not ideal. Considering the lack of high spatial resolution thermal satellite and need of time-series ET dynamics, the MODIS data could be used to provide seasonal actual ET for regional studies. The combination of MODIS and Landsat can be a better choice for future ET study at catchments scale.