Author's Name:	Farag, A.A.; M. A.Abdrabbo; Manal.M.H. Gad EL-Moula; A. F. Abou Hadid & B. A. McCarl
Subject Area:	Life Sciences
Subject	Agricultural
Section	Research Paper

Downscale climatic data- Maximum and minimum temperature - Penman-Montheith equation- RCPs scenarios.

In support of research to predict the impact of climate change on reference evapotranspiration (ETo) in Egypt, this study investigates the projected changes in evapotranspiration in Egypt, with a focus on the Delta, Middle and Upper Egypt. The maximum and minimum temperature were statistically downscaled and compared with a current climate, defined as the period 1971–2000. FAO-56 Penman-Monteith equation was used to estimate ETo by using the climatic data. Evapotranspiration is estimated based on the predicted maximum and minimum using the RCPs scenarios (RCP3.0 – RCP4.5 – RCP6.0 and RCP8.5) during three time series (2011-2040, 2041-2070 and 2071-2100). The obtained results revealed that the maximum and minimum air temperatures were increased under all RCPs scenarios compared to current data. Moreover, the RCP8.5 had the highest maximum and minimum air temperature compared to the other RCPs scenarios. It was found that for all future periods the annual evapotranspiration will increase for the all agro-meteorological zones by uneven values. The main results in this study revealed that ETo significant increase in different tested time series compared to current ETo values. The values of ETo in long term (2071-2100) were higher than short (2011-2040) or mid-term (2041-2070) with respect to the current situation. The highest ETo values was predicted in this study by RCP8.5 during the 2071 – 2100 time series in the Upper Egypt region. The estimation of water requirements for potato crops in different agro-climatic zone show that winter season had the highest cultivated area with potato followed by summer season. Upper Egypt region has the lowest cultivated area of potato during different cultivation season. Total water requirements (WR) for potato during the different cultivating seasons revealed that WR will increase under all scenarios in comparison with the current conditions. The highest water use efficiency was recorded in the Upper Egypt climatic zone during the winter season at 2012. Winter season gave the highest water use efficiency under (WUE) current and future conditions. Moreover, all RCPs scenarios had lower WUE than the current conditions during different time series. Regardless of the seasons, the RCP8.5 gave the lowest WUE in comparison with the other RCPs scenarios.