Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Astronomy and Meteorology

Various atmospheric parameters are in some periods positively and in others negatively correlated with solar activity. In this work a hypothetical scenario to examine this concentration was employed using regional climate model 2RCM3. The solar output was proposed to increase by 1 and 10% respectively and the influence on meteorological variable for wide domain and long period were examined. Primary result show that significant influence exists in the 10% scenario through surface pressure decrease in the north of Africa and south of Africa and north of Saudi Arabia, while through the surface temperature there are increase in all regions in Africa and the Arabian Semi- Island except the region between latitudes +13 to +22 and longitude 0 to +36 which faces decrease, and the relative humidity at the surface level shows a decrease in the region above the equator until below the Cancer Tropic along the west coast of Africa decreases while the region between latitudes +13 to +22 and longitudes +7 to +37 faces increase which is controlling local climate circulation. For the 1% scenario no significant change in the surface pressure, while through the surface temperature there are increase in all regions in Africa and the Arabian semi-Island except the region between latitudes +4 to -7 and longitude +10 to +25 which faces decrease with more decrease at the shore area, and the relative humidity at the surface level shows an increase all over the increase reaches a maximum at the west shore of Africa around the equator while the region in the central area of Africa shows a decrease

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