Accessibility navigation


The impacts of European and Asian anthropogenic sulphur dioxide emissions on Sahel rainfall

Dong, B., Sutton, R. T., Highwood, E. and Wilcox, L. (2014) The impacts of European and Asian anthropogenic sulphur dioxide emissions on Sahel rainfall. Journal of Climate, 27 (18). pp. 7000-7017. ISSN 1520-0442

[img]
Preview
Text (Open Access) - Published Version
· Please see our End User Agreement before downloading.

4083Kb

To link to this article DOI: 10.1175/JCLI-D-13-00769.1

Abstract/Summary

In this study, the atmospheric component of a state-of-the-art climate model (HadGEM2-ES) has been used to investigate the impacts of regional anthropogenic sulphur dioxide emissions on boreal summer Sahel rainfall. The study focuses on the transient response of the West African monsoon (WAM) to a sudden change in regional anthropogenic sulphur dioxide emissions, including land surface feedbacks, but without sea surface temperature (SST) feedbacks. The response occurs in two distinct phases: 1) fast adjustment of the atmosphere on a time scale of days to weeks (up to 3 weeks) through aerosol-radiation and aerosol-cloud interactions with weak hydrological cycle changes and surface feedbacks. 2) adjustment of the atmosphere and land surface with significant local hydrological cycle changes and changes in atmospheric circulation (beyond 3 weeks). European emissions lead to an increase in shortwave (SW) scattering by increased sulphate burden, leading to a decrease in surface downward SW radiation which causes surface cooling over North Africa, a weakening of the Saharan heat low and WAM, and a decrease in Sahel precipitation. In contrast, Asian emissions lead to very little change in sulphate burden over North Africa, but they induce an adjustment of the Walker Circulation which leads again to a weakening of the WAM and a decrease in Sahel precipitation. The responses to European and Asian emissions during the second phase exhibit similar large scale patterns of anomalous atmospheric circulation and hydrological variables, suggesting a preferred response. The results support the idea that sulphate aerosol emissions contributed to the observed decline in Sahel precipitation in the second half of the twentieth century.

Item Type:Article
Refereed:Yes
Divisions:Faculty of Science > School of Mathematical, Physical and Computational Sciences > NCAS
Faculty of Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
ID Code:37053
Publisher:American Meteorological Society

Download Statistics for this item.

University Staff: Request a correction | Centaur Editors: Update this record

Page navigation