Adopting regional calibration scenarios for ensuring reliable ET_o estimates in semi-arid regions: assessing the ancillary data supply method

ABSTRACT

Reference evapotranspiration (ET_o) is an essential parameter of the hydrologic cycle that plays a key role in the water resources management, especially in arid and semi-arid regions where the total amount of annual precipitation is low. Accurate information on ET_o values would be essential for irrigation scheduling and water resources planning as well as water allocation policies. Due to the difficulties involved in the precise direct measuring of this parameter, indirect methods should be adopted and validated in different data completeness scenarios. Although local estimation of ET_o using indirect methods is a way to achieve reliable estimations of this parameter, assessing external/regional scenarios for evaluating these methods would be necessary, since lots of regions suffer from the lack of necessary meteorological records for the ET_o estimation. The present paper evaluated different spatial (external) data management scenarios for adopting the most commonly used empirical equations under ancillary data supplanting in semi-arid regions. The obtained results revealed that when designed properly, the external data supplying structure for ET_o estimations in a target point would be a suitable way to obtain reliable estimates.

KEYWORDS:

• ET_o
• climate
• empirical equations
• calibration

Disclosure statement

No potential conflict of interest was reported by the authors.