The Eastern Desert of Egypt suffered a protracted period of deformation triggered by cratonization of the new juvenile crust known as the Arabian Nubian Shield(ANS),which has been proposed for potential gold discoveri...The Eastern Desert of Egypt suffered a protracted period of deformation triggered by cratonization of the new juvenile crust known as the Arabian Nubian Shield(ANS),which has been proposed for potential gold discoveries associated with the corresponding tectonic event.The Fatira area,on the border of Egypt’s Northern and Central Eastern Deserts,is covered with metavolcanic rocks twisted by a dextral relocation of the Fatira Shear Zone(FSZ)relative to the Barud magmatic body.The recent study evaluated many deformed post-orogenic granitic intrusions and felsite dikes associated with promising mineralization localities,notably orogenic gold deposits.The combination of various field observations and remote sensing data,followed by the analysis of aeromagnetic enhanced maps,allowed the differentiation of distinct lithologies,structural features,and hydrothermal alterations in the study area.Additionally,the integrated results obtained from the different interpretation techniques are utilized to identify and confirm the previously supposed mineralized localities in the Fatira and Abu Zawal areas and predict other matched localities.The final ASTER,Sentinel 2 hydrothermal alteration,and orientation entropy heat maps demonstrate the association between these mineralized regions and major structures related to the FSZ late stage of deformation rather than other structures studied throughout the area of interest.展开更多
This study assesses the direct and indirect effects of natural and anthropogenic aerosols （e.g., black carbon and sulfate） over West and Central Africa during the West African monsoon （WAM） period （June-July-Aug...This study assesses the direct and indirect effects of natural and anthropogenic aerosols （e.g., black carbon and sulfate） over West and Central Africa during the West African monsoon （WAM） period （June-July-August）. We investigate the impacts of aerosols on the amount of cloudiness, the influences on the precipitation efficiency of clouds, and the associated radiative forcing （direct and indirect）. Our study includes the implementation of three new formulations of auto-conversion parameterization [namely, the Beheng （BH）, Tripoli and Cotton （TC） and Liu and Daum （R6） schemes] in RegCM4.4.1, besides the default model＇s auto-conversion scheme （Kessler）. Among the new schemes, BH reduces the precipitation wet bias by more than 50% over West Africa and achieves a bias reduction of around 25% over Central Africa. Results from detailed sensitivity experiments suggest a significant path forward in terms of addressing the long-standing issue of the characteristic wet bias in RegCM. In terms of aerosol-induced radiative forcing, the impact of the various schemes is found to vary considerably （ranging from -5 to -25 W m-2）.展开更多
基金The Egyptian ministry for higher educationthe Stipendium Hungaricum scholarship are thanked for funding the first and third authors under the joint executive program between Hungary and Egypt。
文摘The Eastern Desert of Egypt suffered a protracted period of deformation triggered by cratonization of the new juvenile crust known as the Arabian Nubian Shield(ANS),which has been proposed for potential gold discoveries associated with the corresponding tectonic event.The Fatira area,on the border of Egypt’s Northern and Central Eastern Deserts,is covered with metavolcanic rocks twisted by a dextral relocation of the Fatira Shear Zone(FSZ)relative to the Barud magmatic body.The recent study evaluated many deformed post-orogenic granitic intrusions and felsite dikes associated with promising mineralization localities,notably orogenic gold deposits.The combination of various field observations and remote sensing data,followed by the analysis of aeromagnetic enhanced maps,allowed the differentiation of distinct lithologies,structural features,and hydrothermal alterations in the study area.Additionally,the integrated results obtained from the different interpretation techniques are utilized to identify and confirm the previously supposed mineralized localities in the Fatira and Abu Zawal areas and predict other matched localities.The final ASTER,Sentinel 2 hydrothermal alteration,and orientation entropy heat maps demonstrate the association between these mineralized regions and major structures related to the FSZ late stage of deformation rather than other structures studied throughout the area of interest.
文摘This study assesses the direct and indirect effects of natural and anthropogenic aerosols （e.g., black carbon and sulfate） over West and Central Africa during the West African monsoon （WAM） period （June-July-August）. We investigate the impacts of aerosols on the amount of cloudiness, the influences on the precipitation efficiency of clouds, and the associated radiative forcing （direct and indirect）. Our study includes the implementation of three new formulations of auto-conversion parameterization [namely, the Beheng （BH）, Tripoli and Cotton （TC） and Liu and Daum （R6） schemes] in RegCM4.4.1, besides the default model＇s auto-conversion scheme （Kessler）. Among the new schemes, BH reduces the precipitation wet bias by more than 50% over West Africa and achieves a bias reduction of around 25% over Central Africa. Results from detailed sensitivity experiments suggest a significant path forward in terms of addressing the long-standing issue of the characteristic wet bias in RegCM. In terms of aerosol-induced radiative forcing, the impact of the various schemes is found to vary considerably （ranging from -5 to -25 W m-2）.
