Abstract
Reference evapotranspiration (ET0)estimates have been computed on a globalscale using a high-resolution monthlyclimate dataset. Penman-Monteith (PM) andHargreaves (HG) methods have been compared,showing very reasonable agreement betweenthe two methods. Fitting the two parametersof HG using the PM derived ET0 valuesdid not improve estimates by the HG methodsubstantially. Modifying the originalHargreaves method to a Modified-Hargreaves(MH) method by including a rainfall termimproved ET0 estimates significantlyfor arid regions. When a certain level ofinaccuracy in the meteorologicalobservations was assumed, calculatingET0 by PM and MH, given theseinaccuracy in observations, showed that MHperformed better than PM in reproducingoriginal calculations of ET0 ascalculated by PM assuming no data error. Itis concluded that the PM is a recommendedmethodology if accurate weather datacollection can be expected, but otherwiseMH should be considered.
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Droogers, P., Allen, R.G. Estimating Reference Evapotranspiration Under Inaccurate Data Conditions. Irrigation and Drainage Systems 16, 33–45 (2002). https://doi.org/10.1023/A:1015508322413
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DOI: https://doi.org/10.1023/A:1015508322413