This study aims to investigate the standardized precipitation evapotranspiration index (SPEI) using the monthly observed and gridded Climate Research Unit (CRU) dataset across 13 stations in Ethiopia during the period 1970–2005. SPEI is computed at a 4-month timescale to represent drought during the Belg (February–May) and Kirmet (June–September) seasons separately, and at an 8-month timescale to represent the drought during these two seasons together (February–September). The results show that there are extremely strong correlations (R ≥ 0.8) between the estimated precipitation values from CRU and the observed values, with root mean square error (RMSE) of 4–99 mm and mean percentage error (MPE%) of −30 to 73% at most stations. For temperature and SPEI, the CRU shows almost strong correlations (0.6 ≤ R < 0.8), while the dominant values of RMSE and MPE are 0.7–5 °C and −22 to 26%, respectively, for temperature and 0.28–0.96 and −49 to 55%, respectively, for SPEI during the three seasons. It is also found that each of the SPEI clusters (dry, normal, and wet) estimated from CRU has a high success percentage (≥ 60%) at more than 50% of the stations, while the general accuracy exceeds 60% for the three SPEI clusters together at more than 75% of the stations. Finally, the correct hits for the estimated SPEI clusters from CRU are often within the corresponding observed cluster but may shift into another category (extreme, severe, and moderate) except for a few events.

This study aims to assess the impact of using different fuels in Egyptian Titan Alexandria Portland Cement Company on emissions and concentrations of pollutants (Total suspended particles (TSP), nitrogen dioxide (NO₂‎), and sulfur dioxide (SO₂)) and their influence on ambient air quality during the period 2014–2020 using AERMOD dispersion model. The results showed that changing the fuel from natural gas in 2014 to coal mixed with alternative fuels (Tire-Derived Fuel (TDF), Dried Sewage Sludge (DSS), and Refuse Derived Fuels (RDF)) in 2015–2020 caused fluctuating variations in pollutant emissions and concentrations. The highest and lowest maximum concentrations of TSP occurred in 2017 and 2014 respectively, where the TSP is positively correlated with coal, RDF, and DSS and negatively correlated with natural gas, diesel, and TDF. Also, the lowest and highest maximum NO₂ concentrations were detected in 2020 and 2016 followed by 2017 respectively, where NO₂ is positively correlated with DSS and negatively correlated with TDF and varies with diesel, coal, and RDF. Moreover, the maximum concentrations of SO₂ were the lowest in 2018 and highest in 2016 followed by 2017 because of its considerable positive correlation with natural gas and DSS and negative correlation with RDF, TDF, and coal. Generally, it was found that increasing the percentage of TDF and RDF with decreasing the percentage of DSS, diesel, and coal will reduce pollutant emissions and concentrations and enhance ambient air quality.

This research aims to study and discuss the diabatic heating at the different isobaric levels during interaction between mid-latitude (southward extension of 500 hPa trough) and extra-tropical (northward extension of Sudan monsoon low) cyclones over Egypt and east Mediterranean during the period 3-6 November 2015. Also, relationship between diabatic heating and kinetic energy generation were illustrated. The cyclogenesis of this case is associated with maximum heavy rainfall over northern part of Egypt during growth stage (4-5 November). Throughout the life cycle of cyclone, the vertical advection term ((T/P)) is the significant term that plays an important role in diabatic heating calculation and opposite to adiabatic term (-(/Cp)). The largest contribution of the horizontal cold advection occurs during the pre-storm stage, while the largest warm advection occurs during the growth stage. Finally, it is found also that the area of diabatic cooling (heating) is synchronized with destruction (generation) of kinetic energy.

This study explores the relationships between evapotranspiration (ET), land surface temperature (LST), and the normalized difference vegetation index (NDVI) across Egypt using MODIS satellite data. Given Egypt's distinct climatic conditions, understanding how these key climatic parameters interact is vital for evaluating water and vegetation dynamics in its arid and semiarid regions. The research aims to examine the climatic factors that affect the observed correlations among ET, LST, and NDVI using MODIS satellite data covering the years from 2003 to 2022. The analysis included examining spatial and temporal patterns, as well as calculating correlation coefficients between variables. Findings revealed strong positive correlations between ET and NDVI, particularly in vegetated regions, indicating a close relationship between water availability and vegetation growth. In contrast, negative correlations were found between LST and NDVI, underscoring the impact of temperature on plant health. Further analysis indicated that these correlations were shaped by several significant climatic factors. Areas near water sources, such as the Delta and the Nile Basin, which experience lower temperatures, exhibited stronger positive correlations between ET and NDVI. Conversely, regions with limited water resources and higher temperatures demonstrated weaker or even negative correlations.

Fog is a major aviation hazard that reduces visibility and disrupts airport operations. This study presents the first integrated assessment of fog climatology, operational forecast evaluation, and meteorological controls at King Fahd International Airport, eastern Saudi Arabia, using METAR observations and Terminal Aerodrome Forecasts (TAFs) during 2001–2025. Fog variability, duration, intensity, and associated meteorological conditions were investigated, and TAF performance was evaluated against observed fog events. Fog occurred predominantly during autumn and winter, with the highest frequency in October, and reached a pronounced maximum near 0600 LT. Severe fog was the prevailing intensity type throughout most years. Although annual fog frequency exhibited slight decreasing trends, the annual longest fog duration increased marginally. TAFs successfully predicted only 49% of observed fog days during 2006–2025, highlighting the continuing difficulty of operational fog forecasting. Fog formation was favored by relatively high mean sea-level pressure (1010–1019 hPa), calm to low southerly winds (0–3 m/s), relative humidity of 87–100%, and dew point deficits of 0–2 °C, while wind speed exhibited the strongest statistical association with fog occurrence among the investigated meteorological variables. These findings provide a climatological reference and practical meteorological thresholds for improving aviation fog forecasting and airport operations in coastal arid environments.