Effects of Saharan Mineral Dust Aerosols on the Structure and Energetics of the African Easterly Jet-African Easterly Wave System
Abstract
The African easterly jet (AEJ), African easterly waves (AEWs) and Saharan mineral dust (SMD) aerosols are signature features of the summertime circulation over North Africa. The interaction between the AEJ-AEW system and SMD is crucial to understanding the meteorology over North Africa and the Eastern Atlantic. In this study, the effects of SMD on the AEJ-AEW system are examined for a single summer season using the Weather Research and Forecasting (WRF) model coupled to an online dust model. Two experiments are conducted: one with direct dust-radiative feedbacks and the other without. For both experiments, the WRF-dust model was initialized with ECMWF reanalysis data and then integrated forward in time for three months: July-September 2006. Two aspects of the SMD-modified AEJ-AEW system were examined: The structural changes to the system and the energetics of the system. With SMD, the zonal asymmetry of the AEJ is greatly enhanced, which produces a zonal contraction of the AEWs and slows their westward migration. Calculations show that the SMD increases the energy transfer from the AEJ to the AEWs, resulting in stronger AEWs. These SMD-induced changes to the AEJ-AEW system also result in a northward shift of the north and south tracks of the AEWs. We discuss these results in light of the potential impacts of SMD on the meteorology over North Africa and the eastern Atlantic Ocean.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.A33G0321B
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3355 Regional modeling;
- ATMOSPHERIC PROCESSES