COMPARISON OF REFERENCE EVAPOTRANSPIRATION EQUATIONS UNDER CLIMATE CHANGE CONDITIONS

Author's Name: M. A. A. Abdrabbo & Gamal El Afandi
Subject Area: Life Sciences
Subject Agricultural
Section Research Paper

Keyword:

Climate. Reference Evapotranspiration. Estimation. E-Pan. FAO-56 Penman-Monteith., Blaney-Criddle. Hargreaves. Thornthwaite. RCPs


Abstract

Precise estimation of crop water requirements at any region over the globe is very vital. Hence, an accurate estimation of reference evapotranspiration is very important especially in agriculture, hydrology and meteorology. The objectives of the present study were comparison of evapotranspiration estimations using different equations and FAO-56 Penman-Monteith under future climatic conditions. Four reference evapotranspiration (ETo) methods namely; Blaney-Criddle, Hargreaves, Thornthwaite and FAO-56 Penman-Monteith (PM) have been used. Data of the present climate have collected from different automated meteorological stations distributed along Egypt from 1998 to 2007. While, the future climate data have chosen for the concerned RCPs scenarios: RCP2.6, RCP4.5, RCP6.0 and RCP8.5 at 2040. The results revealed that, there were statistically no significance between PM and Blaney-Criddle only in the Delta region at P value less than 0.05 while the other equations had significant differences. There were significant differences between ETo under current and future conditions for all studied regions. The Blaney-Criddle and Thornthwaite equations had the lowest ETo values under different RCPs scenarios comparing with Hargreaves and Penman-Monteith (PM) method. Generally, RCP 8.5 gave the highest ETo values under climate change conditions.

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