Sulfate Aerosol Impacts on the Tropical Atlantic Rainfall Climate Over the 20th Century


The gradient in sea surface temperature between the northern and southern portions of the tropical Atlantic significantly influences the long-term changes in rainfall, including droughts over West Africa and Northeast Brazil. This gradient has exhibited a long-term, nonperiodic drift from the beginning of the 20th century until the 1980s, with stronger warming in the South relative to the North. DOE funded researchers explored the origins of this trend by analyzing observations along with a multi-model ensemble of 20th century atmosphere-ocean coupled model simulations. Their analysis shows that the trend is unlikely the result of from natural climate variability and that a significant portion of the observed trend likely originates from external climate forcings, specifically sulfate aerosols. The authors conclude that anthropogenic sulfate emissions, originating primarily from industrial activity in the Northern Hemisphere, may have significantly altered the tropical Atlantic rainfall climate over the 20th century.


Chang, C. Y., J. C. H. Chiang, M. F. Wehner, A. Friedman, and R. Ruedy. 2010. “Sulfate Aerosol Control of Tropical Atlantic Climate Over the 20th Century,” Journal of Climate, Available on Early Online Release.