Northern Africa has been subject to extensive droughts in the late 20th century, which are frequently linked to changes in the Sea Surface Temperature (SST) in both the Atlantic and Indian Oceans. However, climate models forced by observed Sea Surface Temperatures have been unable to reproduce the magnitude of rainfall reduction over the last several decades. In this study, we propose that aerosol indirect effects (AIE) may be an important feedback mechanism to contribute this recent reduction. The climate model used here has a fully predictive aerosol life cycle. Results are presented for a set of sensitivity experiments designed to distinguish the role of aerosol direct/semi-direct and indirect effects on regional precipitation. Changes in cloud lifetime due to the presence of carbonaceous aerosols are proposed as a key mechanism to explain the reduced rainfall over the tropical and North Africa.
Revised: September 8, 2016 |
Published: June 16, 2016
Citation
Yoon J., P.J. Rasch, H. Wang, V. Vinoj, and D. Ganguly. 2016.The Role of Carbonaceous Aerosols On Short-term Variations on Precipitation Over North Africa.Atmospheric Science Letters 17, no. 7:407-414.PNNL-SA-88624.doi:10.1002/asl.672