In this paper, we will investigate the influence of the microphysics schemes on the rainfall pattern of the extreme storm that impacted Egypt on 12 March 2020. The aim is to improve rainfall forecasting using the numerical Weather Research and Forecasting (WRF) model for an effective Early Warning System (EWS). The performance of six microphysics schemes were evaluated using the Model Object-based Evaluation analysis tool (MODE) forced by three selected satellite-based datasets (CMORPH, PERSIANN, PERSIANN-CCS, etc.) and one reanalysis dataset (ERA5). Six numerical simulations were performed using the WRF model, considering the following microphysics schemes: Lin, WSM6, Goddard, Thompson, Morrison, and NSSL2C. The models were evaluated using both conventional statistical indices and MODE, which is much more suitable in such studies. The results showed that the Lin scheme outperformed the other schemes such as WSM6, Goddard, Thompson, Morrison, and NSSL2C, in rainfall forecasting. The Thompson scheme was found to be the least reliable scheme. An extension for this study is recommended in other regions where the observational rain gauges data are available.

A regional climate model (RegCM4) was used to project the potential evapotranspiration (PET) of Egypt under two future scenarios: RCP45 and RCP85. Spatially, the RegCM4 has a higher PET under the RCP85 than the RCP45. Among all locations, the RegCM4 was able to capture the monthly variability in PET with respect to the Climate Research Unit (CRU). In addition, the simulated PET was notably improved when a linear regression model (LRM) was used. Further, future PET projects a strong increased trend under the RCP85; meanwhile, future PET projects a weak increased trend under the RCP45.

Several heatwaves (HWs) have been recorded in Egypt in recent years. Some of these HWs were mild, while others were severe and resulted in mortalities and morbidities. On the other hand, air pollution is considered a health issue in Egypt’s megacities, especially the capital city, Cairo, and its surroundings, the Greater Cairo (GC) region. In this study, we examine a number of HWs that have hit Egypt in recent years, along with the state of air quality, in terms of PM10, NO₂, and O₃, during the period of HW incidence, with a focus on the GC region. During the period of study, the frequency, intensity, and duration of HWs have been observed to increase. The total number of recorded HW events was 190, encompassing 376 HW days. The time series of daily mean NO₂ showed no correlation with temperature during the months that experienced HWs cases. Conversely, PM10 and O₃ concentrations exhibited a similar pattern as that of the daily maximum temperature. This increase in the two pollutant concentrations led to a degradation of the air quality, as demonstrated by the fact that the Air Quality Health Index went from “moderate risk”, on normal days, to “high risk” during the HWs.

This paper discusses the aerosol radiative effects involved in the accuracy of shortwave net radiation, $R_{n.sw}$ , with $sw\in$ (400–900) nm, retrieved by the Operational Land Imager (OLI), the new generation sensor of the Landsat mission. Net radiation is a key parameter for the energy exchange between the land and atmosphere; thus, $R_{n.sw}$ retrieval from space is under investigation by exploiting the increased spatial resolution of the visible and near-infrared OLI data. We adopted the latest version of the Second Simulation of a Satellite Signal in the Solar Spectrum (6SV) atmospheric radiative transfer model implemented in the atmospheric correction algorithm (OLI Atmospherically-Corrected Reflectance Imagery (OLI@CRI)) developed specifically for OLI data. The values of $R_{n.sw}$ were obtained by varying the microphysical properties of the aerosol during the OLI@CRI retrieval of both the OLI surface reflectance, ${\rho }_{pxl}^{oli}$ , and the incoming solar irradiance at the surface. The analysis of the aerosol effects on the $R_{n.sw}$ was carried out on a spectrally-homogeneous desert area located in the southwestern Nile Delta. The results reveal that the $R_{n.sw}$ available for energy exchange between the land and atmosphere reduces the accuracy (NRMSE ≃ 14%) when the local aerosol microphysical properties are not considered during the processing of space data. Consequently, these findings suggest that the aerosol type should be considered for variables retrieved by satellite observations concerning the energy exchange in the natural ecosystems, such as Photosynthetically-Active Radiation (PAR). This will also improve the accuracy of land monitoring and of solar energy for power generation when space data are used.

The regional climate model (RegCM4) was used to project the maximum and minimum air temperatures (T_max and T_min) of Egypt considering the worst-case scenario: Representative Concentration Pathway 8.5 (RCP8.5). To achieve this goal, the spatial pattern of the simulated T_max and T_min was first examined. After that, the simulated T_max and T_min were bias-corrected in the historical period with respect to station observations using the Linear-Scaling (LS) technique. Finally, the LS was used to correct the two future scenarios. To downscale the RegCM4, the medium resolution of the Earth System Model of the Max Planck Institute (MPI-ESM-MR) was used to provide the lateral boundary condition and sea surface temperature. The results showed that both T_max and T_min exhibit the highest increase in the far-future period (2081–2100) particularly over Western Egypt, the Red Sea, and Upper Egypt (by 4–6 °C). Additionally, the RegCM4 performance is remarkably improved when the LS method is used. Such performance is indicated by a low mean bias in the validation period compared to the evaluation period over majority of stations. Further, the added value of the LS is noted in T_min more than T_max. Therefore, the RegCM4 can be used to project the T_max and T_min using the LS over the location of interest. In addition, using multiple General Circulation Models (GCMs) is necessary to account for uncertainty associated with the atmospheric forcing.

New Nuclear Power Plant (NPP), which is under construction in El Dabaa, Egypt, is expected to start working within few years. Such project should be associated with several scientific research works. The suitability of the NPP location as well as the assessment of the impact of its routine work and accidental failure is among the points that should be addressed. In this work, the contamination risks due to uniform accidental leakage of the radioactive aerosol $C_{}^{137}s$ that continues for eight hours is studied. FLEXPART version 10.4 at high resolution (55 km) is applied using six-hour NCEP FNL (1° × 1°) gridded data to simulate the dispersion and deposition of $C_{}^{137}s$ for the subsequent five days. This process is repeated each day for the period of 2008 to 2018. It is shown that high concentration and total deposition are observed particularly during the summer season. In addition, the consideration of different emission scenarios indicates that Egypt is expected to be strongly affected. Moreover, dispersion and concentration of the radioactive materials is notably influenced by near-surface winds. In conclusion, FLEXPART is considered as a promising tool to explore the possible nuclear hazards under a variety of meteorological conditions. Further, a future study will consider the influence of the horizontal grid spacing and lateral boundary condition using the coupled Weather Research and Forecasting (WRF)-FLEXPART system.