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Climate changes associated with high-amplitude Sq geomagnetic variations

Rabeh T., Carvalho F., Khalil A., El-Aal E.A., El-Hemaly I.

Acta Geophysica

2011

Vol. 59, no. 5

1044-1056

When the solar irradiance propagates between the outer magnetospheric regions and the ionosphere, dynamic processes of the magnetosphere-ionosphere-thermosphere system are affected at the lower end of their paths by the interaction of radiation with the neutral troposphere. The main target of this work is to investigate the relationship between the diurnal magnetic field variations resulting from solar activities and the variation in the troposphere temperature. Meteorological and geomagnetic data acquired from different observatories located in Egypt, Portugal and Slovakia in a long-term and daily-term scales were analyzed. The long-term results show that there is a close relationship between the diurnal Sq magnetic field variations and the tropospheric temperature. The rate of temperature increase at mid-latitude areas is higher than at high-latitude. During the period of investigation, it is found that the troposphere temperature has increased by about 0.033 °C/year at Helwan, Egypt, 0.03 °C/year at Coimbra, Portugal, and 0.028 °C/year in Hurbanovo/Stará Lesná, Slovakia. The Sq geomagnetic variations depend on the intensity of the electric currents generated by the effect of solar radiation in the ionosphere.

Tectonic model of Egypt based on magnetic analysis

Rabeh T., Ernst T.

Acta Geophysica

2009

Vol. 57, no. 3

680-695

The main target of this work was to study the dynamics of the Earth's crust for Egypt based on the magnetic survey. High-resolution land magnetic data were analyzed, combined with the results of GPS and seismic stress analyses. The constructed tectonic map shows that the N35°-N45°W trend of the structure (related to the Red Sea and Gulf of Suez tectonics) predominates along the Gulf of Suez, Red Sea, covering wide parts of the study area. The N45°-N65°E tectonic trend (related to the Syrian Arc tectonics), prevailing in the northern part of Egypt, is of the second rank. The Aqaba (N15°-25°E) and E-W trends prevail in the northern part and along the transition zone of stable/unstable shelves. The depth to the basement rocks ranges from the surface along the Red Sea and southern parts of Egypt to more than 4 km below sea level at the northern part of the study area. The results also show that the opening rate along the Red Sea was faster in the past than nowadays. Furthermore, a preliminary kinematics model is proposed.