The objective of this paper is to investigate
the suitability of various ETo estimation methods and to
calibrate them for use in short-term irrigation planning and operational
studies in the GMIA. Ten methods, ranging from simple temperature-
based to complex data-intensive combination methods
were considered in this study. The first part of this paper describes
the theoretical details of the selected ETo estimation methods,
including the estimation of parameters associated with these
methods, followed by a discussion of the performance and calibration
of these methods at three study sites in southeast Australia.