J. Clim. http://doi.org/hrb (2012)
Multidecadal variations in sea surface temperature in the North Atlantic Ocean, known as the Atlantic Multidecadal Oscillation, are associated with extreme events such as droughts, floods and hurricanes. Interactions between rainfall, dust and sea surface temperatures help to sustain the Atlantic Multidecadal Oscillation, according to an analysis of meteorological data.
Chunzai Wang of the NOAA Atlantic Oceanographic and Meteorological Laboratory, Miami, and colleagues used meteorological and dust data from the past 60 years to examine the relationship between North Atlantic sea surface temperatures, aerosols and rainfall over the Sahel. They identify a link between the warm phase of the Atlantic Multidecadal Oscillation and high rainfall in the Sahel. Increased rainfall, in turn, is accompanied by a reduction in atmospheric aerosol levels over the semi-arid regions of Africa, and a concomitant decline in the transport of dust offshore.
A reduction in dust levels over the tropical North Atlantic could warm the surface ocean, and set in motion a positive feedback between the Atlantic Multidecadal Oscillation and rainfall in the Sahel.