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Sulfate Aerosol Evolution

Researchers at NCAR used the CCM3 model to show global sulfate aerosol evolution and how sulfate aerosols are transported between different continents. The sulfate aerosols shown here are primarily from man-made sources including coal burning and copper smelting. Other natural sources (20% of the total) such as dimethyl sulfide produced by phytoplankton in the ocean and volcanic emissions are not modeled in this case study.


Global Sulfate Aerosols


Sulfate Aerosols by Region


QuickTime | MPEG 1.4 MB

The animation shows daily averages of sulfate aerosols across the globe.

QuickTime | MPEG 2 MB

Daily averages of sulfate aerosols across the globe color-coded by regional source using isorsurfaces (1.0 ppbv). Red is North America, Orange is Europe, Blue is Asia, and Violet is the rest of the World.

Emissions are seasonal. For example, in Europe, there tends to be more coal buring during the winter to produce energy for heating. In the US, however, emissions are more constant. Like Europe, coal is burned in the winter to produce power for heat, but because of energy demands for air conditioning systems, which are more prevalent in the US than in Europe, yearly sulfate emissions are more constant in North America.

Seasonal variations, however, are dominated by the chemical process of converting sulfides into sulfate aerosols. A process which requires sunlight and water vapor. These elements are more prevalent in the North American summer, and so we see peak levels in June, July, and August.

There are two main effects from the increased sulfate aerosol levels in the atmosphere: the direct and indirect effects. The direct effect is that radiation is scattered back into space resulting in less energy entering the climate system. Some theories propose that this leads to a cooler climate and helps mitigate global warming.

The indirect effect is that the sulfate aerosols act as cloud condensation nuclei resulting in the formation of more drops compteting for the same amount of water vapor. This produces clouds that persist longer and that have smaller droplets that do not precipitate as easily, and they are brighter, reflecting even more radiation. This, in turn, may offset the greenhouse effect.

Model Name:
NCAR Community Climate Model (CCM3)
Data Size:
1 GB
January 1
Time Evolution:
1 year
Time Resolution:
1 day
Horizontal Real World:
Spatial Resolution:
Tim Scheitlin, NCAR, SCD

Phil Rasch
Mary Barth
Jeff Kiehl

Date Created:
Date Catalogued:
© 2002, UCAR, All rights reserved.