Effects of the Subtropical Anticyclones Over North Africa and Arabian Peninsula on the African Easterly Jet

North African climate is analyzed between 1979 and 2010 with an emphasis on August using the European Center for Medium Range Weather Forecast (ECMWF) global data set to investigate the effects of the subtropical anticyclones over North Africa and the Arabian Peninsula on the Africa Easterly Jet (AEJ). It was found that the AEJ encloses a core with a Local Wind Maximum (LWM) in West and East Africa, respectively, in which the west LWM core has a higher zonal wind speed. The strength of both cores is distinctly different by way of thermal wind balance. As found in previous studies, the AEJ is formed through baroclincity with influence from Saharan low heating along the Inter-Tropical Convergence Zone (ITCZ). Since there are two separate anticyclonic centers, the AEJ is maintained by the anticyclonic systems in West Africa, East Africa as well as the Arabian Peninsula. The presence of these two anticyclonic centers provides the AEJ with two separate core maxima with the western LWM located at (15°W,17°N) and the eastern LWM located at (35°E,15°N) for August. The AEJ has significant influence on the maintenance and propagation of African Easterly Waves (AEWs) especially during the month of August. The focus of this research is to understand the role of the Arabian high on the eastern LWM as it complement with the Saharan high and western LWM. An intense eastern LWM will help lead to convective development established through orographic effects from the high terrains of the Ethiopian Highlands and Asir Mountains. This will help explain further how convection and easterly waves are formed and maintained for long periods of time.