| Climate change poses significant challenges to regions worldwide, and Egypt stands particularly vulnerable to its effects. This study aims to assess the impact of climate change on maximum daily rainfall depths across various return periods for the whole of Egypt. Initial data collection involved gathering historical datasets from diverse sources, including GPM data, PDIR data, and Tutiempo online data. Subsequent consistency assessments were conducted using field-measured records, employing statistical tests such as RMSE, MAE, R2, and NSE across six rainfall stations. After the verification process, Tutiempo dataset emerged as the best historical dataset, serving as a calibration reference for climate model data.
Climate model datasets from the African Cordex domain, encompassing 18 different models under RCP4.5 and RCP8.5 scenarios (CMIP5). Interquartile bias method was used to correct the historical climate period using Tutiempo dataset to generate the projected future maximum daily rainfall depths for 21 rainfall stations in Egypt. The rainfall analysis reveals a reduction in the maximum daily rainfall depths across all country zones at various return periods (100, 50, 10, and 5 years), using the median value for all climate models. Notable extreme reductions in the southwest desert areas, affecting Dakhla, El-Kharga, and Assuit with reductions ranging from 63% to 85%. The reduction ratios decrease as we move north and east. Coastal zones, including Marsa Matroh, Alexandria, and El-Tor, experience the lowest reductions ranging from 2% to 45%.
The maximum reduction ratio occurs for the 100-year return period and decreases for the 50, 10, and 5 year return periods. Due to the uncertainty of climate change models, few climate scenarios give an increase in the future maximum daily rainfall depth for some rainfall stations, ranging from 1.8% to 205% at Al-Dakhla and El-Tor, respectively. In order to assess the effect of uncertainty in climate change on rainfall intensity, IDF curves for 21 rainfall stations were created, containing a range of curves illustrating the lower and maximum limits and the best value (median) from all climate change scenarios, and the final decision is left to the decision-makers.
Finally, these findings highlight the urgency of adaptive measures to adapt to the adverse impacts of climate change on Egypt's hydrological systems and water resources management.
| Abstract |