Potential Evapotranspiration Under Present and Future Climate

Abstract

The objective of this chapter was to calculate potential evapotranspiration (PET) values for five governorates in Egypt (North Sinai, Marsa Matrouh, El-Gharbia, El-Sharkia and Sohag) using Penman-Monteith equation with climate normals values (1985–2014). These calculated values of PET was used in next chapters to calculate water requirements for the prevailing and suggested crops structures. Furthermore, the effect of climate change on PET was assessed using comparison between RCPs scenarios developed from four global models and the boundary of the more close scenario to the measured data was input into a regional climate model (WRF-RCM) to develop more accurate weather data to be used in PET calculation under climate change. The methodology described in this chapter resulted in achieving higher level of certainty in the prediction of weather elements with 92 % degree of accuracy. Thus, we used these data to calculate PET values under climate change in 2030. The results indicated that the values of weather elements and PET were slightly higher in North Sinai and Marsa Matrouh. The difference in PET was increase in El-Gharbia and El-Sharkia governorates and in 2030 it was be noticeably high in Sohag governorate. These increases will have its negative implication on water consumption by the cultivated crops in these governorates. Therefore, it is important for policy makers in Egypt to be alert on these anticipated risks associated with climate change in 2030.