Here, statistical analysis for the emissions of some pollutants over Egypt during the period from 1850 to 2000 using the ACCMIP-History emission inventory dataset has been done. The seasonal and annual variations of the following compounds: Black Carbon (BC), Carbon monoxide (CO), Propane (C3H8), Formaldehyde (HCHO), Nitrogen Oxides (NOX), Toluene (C7H8), Ethylene (C2H4), Ammonia (NH3), Propene (C3H6), Sulfur Dioxide (SO2) and Organic Carbon (OC) have been examined. It is found that these pollutants are intense over Nile Delta and Greater Cairo (30.25º - 31.75º E and 29.25º - 31.25º N); it produces mainly from human activities. The annual analysis of these pollutants illustrates that four of them (BC, OC, CO, C2H4 and C3H6) have the same behavior during the study period, where an obvious increase appears from about 1930 to 2000. Also there are four pollutants (NOx, C7H8, SO2, C3H8 and HCHO) that have the same behavior, where an evident increase appears from 1950 to 2000. The coefficient of variation (COV) largest values appearances in seasonal and annual time series of HCHO, SO2 and C3H8 while the smallest values found in the C2H4, CO, OC and C3H6 time series. The analyses of trends show that an clear increase of all pollutant emissions with the seasonal and annual time series during the period 1850-2000, while during a period 1930-2000 the analyses of trends indicate that an obvious increase of all pollutants emission except with NH3 wherever a negative trend seems with the seasonal and annual time series.

In this paper a proposed apparatus for seawater desalination at low temperature and low pressure is discussed. Based on the idea of Torricelli barometer, water vapor above seawater and water vapor above fresh water are forced to gather in a tube connecting the two water sources. Creating temperature difference between the two water sources in nearly vacuum environment develops large pressure difference. This pressure difference between the two water vapor sources forces evaporated water from the hotter seawater surface to condense in the cooler fresh water area. The apparatus automatically substitutes the evaporated seawater and transmits the fresh water to where it is needed, i.e. no energy is required to feed the apparatus with seawater or to transfer fresh water. The apparatus also automatically get rid of brine (more salty seawater due to evaporation) by replacing with fresh seawater. The variability of atmospheric surface pressure due to season change or the passage of atmospheric systems that can disturb the apparatus performance is also considered. The study indicates, theoretically, that this technique which was known to be suitable for small-scale freshwater needs can yield several orders of magnitude than expected. Theoretically, it is shown that with the simple proposed apparatus, the estimated fresh water yield can be more than 10 m3 per day. Experiments are required to test the idea.

The impact of solar radiation and temperature on wheat cultivars can lead to increase or decrease the productivities. Thus, the objective of this study was to explain are the solar radiation and temperature affecting the different growth stages of wheat cultivars that grow under different agro-climatic conditions in Egypt and their productivities. So, we select maximum and minimum productivities for two wheat cultivars (Giza168 and Sakha93) at different governorates in Egypt to clarify its depending on solar radiation and temperature. Productivity data were collected (2003/04-2011/12 growing seasons), as well as days to different growth seasons and weather data to be used in our study. It is found that Heading, Grain milk and Stem elongation stages have the most influential on wheat yields in Egypt depending on maximum temperature and solar radiation. These results explain that the difference between maximum and minimum productivity in Kafr El-Sheikh and El-Gharbia governorates were smaller than that difference in El-Minya and Sohag governorates. This is because the higher impact of weather elements was only in the grain milk stage in Kafr El-Sheikh, heading stage in El-Gharbia and Heading, Grain milk and Stem elongation stages in El-Minya and Sohag. Thus, season with higher solar radiation in Stem Elongation stage and maximum temperature in Heading and Grain milk stages, the productivity will decrease during this season. Otherwise, with normal solar radiation and temperature, the productivity will increase during this season.

Wind is one of the main significant renewable energy resources all over the globe. It could be used to overcome the increasing energy power demand in Egypt and Sudan. In addition, it is a good source of clean energy that could be used to reduce air pollution in both countries. The main objective of this research is to evaluate the performance of the Weather Research and Forecasting (WRF) model to predict wind speed over Egypt and Sudan. Nineteen weather stations were selected from both countries for this purpose. In addition, Willmott Index of agreement (WI), Coefficient of Determination (R2), Normalized Root Mean Square Error (NRMSE) and Normalized Mean Bias Error (NMBE) were used in the evaluation processes. Its performance was high during autumn in Egypt and winter in Sudan, while it was low during summer in both countries. In addition, strong correlations were found between measured and forecasted wind speed for the selected days during all seasons. In the same time, WI and R2 values approximately close to 1, while NRMSE and NMBE were approaching to zero. Therefore, there is no significant difference between the real and forecasted wind speed during all seasons. Overall results proved the capability of the model to predict wind speed over Egypt and Sudan compared to measurements. Therefore, it may conclude that both Egypt and Sudan can depend on the WRF model to predict wind speed in the past, present, and future with high accuracy.

Semi-miner axis of the ellipse orbit of the Earth around the Sun decreases with the increase of eccentricity. It follow that the seasonal change increases, and the length of the seasons change. Nowadays the climate with the northern star is Polaris in the northern hemisphere. Winter and summer are weak in the northern hemisphere. So that, Nile flood is expected to be fair good. When the obliquity is going to decrease that means the tropics area is decreased and then middle latitude activity affects on the north Africa and Mediterranean Sea area. According to Milankovitch both the eccentricity and the obliquity will decrease in the following three thousand years. So that we expect the Nile flood will be weak, but in the same time the middle latitude rain in winter, spring, and autumn will increase.

This paper examines the sensitivity of the development of the convective planetary boundary layer (PBL) height to three different land surface models [LSMs; i.e., Community Land Model, version 4.0 (CLM4.0); Noah LSM; and The Rapid Update Cycle (RUC)] that are used in Weather Research and Forecast model (WRF) with the Advanced Research core (WRF-ARW). The model simulation covers a 48-h forecasts during summer in Sahara Desert, and evaluated against reference reanalysis NCEP Global Data Assimilation System (GDAS). Results of the sensitivity experiments indicate that Performance of the LSMs is found to be generally inferior to that of the reanalysis NCEP Global Data. The PBL height is most sensitive to the amount of sensible heat flux for RUC and CLM4 models more than Noah model. RUC model gives higher downward long wave radiation in comparison to Noah and CLM4 models which enhance the sensible heat flux at the emission. Model sensitivity to upward heat flux at ground surface over Sahara Desert is also discussed.