GIS Tool for Distribution Reference Evapotranspiration under Climate Change in Egypt

Current climatic data were collected to estimate ETo from 1998 to 2007 in the major Egyptian agro-climatic regions, i.e. Delta region, Middle Egypt and Upper Egypt, to generate future mean air temperature under climate change conditions using Magicc\Scengen model. FAO-56 Penman-Monteith equation was used to estimate ETo by using the collected and generated climatic data. The climate change data were generated under four scenarios (A1, A2, B1 and B2, according to IPCC results revealed that ETo significantly increased in 2050s and 2100s compared to the current ETo values. Results indicated that the values of ETo in 2100s were higher than those for 2050s for all studied regions. The average percentages increase in the four tested scenarios of the 2100s for Delta, Middle Egypt and Upper Egypt were 14, 17 and 18%, respectively. The most affected region by climate change was Upper Egypt because it already has the highest ETo under the current conditions; this increase in ETo could affect agricultural expansion negatively, especially if the water resources become a limiting factor. Moreover, the spatial analysis using kriging interpolation showed that the ETo in Egypt will be increased by uneven values under future climate change, the highest increasing values will appear under the A1 scenario, while the lowest increasing will be observed under B1 and B2 scenarios.