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Communication incl. Poster: BibTeX citation key:  Zhanga
Zhang, C., Huang, J., Prospero, J. M., Wang, C. & Issoufou, H. B. A. 2009. Effect of African Aerosol on Precipitation along the Guinea Coast. Work presented at Third International AMMA Conference, July 20—24, at Ouagadougou, Burkina Faso.
Added by: Devic 2009-09-08 10:58:08    Last Edited by: roussot 2009-10-18 20:21:54
 B  
Categories: Aerosol and Chemistry
Keywords: Aerosol, Climate, Precipitation
Creators: Huang, Issoufou, Prospero, Wang, Zhang
Publisher: African Monsoon Multidisciplinary Analyses (Ouagadougou, Burkina Faso)
Collection: Third International AMMA Conference

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Abstract
Negative correlation between aerosol content and large-scales surface precipitation along the Guinea coast has been observed. Several steps have been made to distinguish possible physical processes behind such negative correlation, including washout of aerosol by rainfall, influences on precipitation by climate and meteorological factors typically associated with aerosol variability, and aerosol effects on rainfall. Efforts are made to (a) compare numerical simulations to observations to identify spatial patterns and temporal behaviors of aerosol washout, (b) isolate effects on rainfall by known climate and weather phenomena, (c) identify higher momentum characteristics of rainfall variation associated with aerosol, such as changes in the rain rate and vertical profiles of associated latent heating, and (d) track the trajectories and sources of aerosol transport and their time-lag relationships with rainfall variability. The negative correlation exists in both daily and monthly mean data. Aerosol washout as a possible interpretation can be reasonably ruled out. Known climate and weather factors (including water vapor) cannot explain the amplitudes of the observed rainfall variations associated with aerosol in a linear sense. The observed changes in precipitation are due mainly to rainfall with light to moderate rain rates and are larger over ocean than over land, consistent to our current understanding of aerosol effects on precipitating cloud. The source of aerosol in this region has been traced to North Africa, especially the Bodele suppression. The negative correlation exists between precipitation and upstream aerosol along their trajectories with a lead of 1 – 3 days. All these results suggest that the observed negative correlation between precipitation and aerosol may be taken as observational evidence of large-scale aerosol effects on precipitation over West Africa.
Last Edited by: roussot