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DOE Pulse
  • Number 351  |
  • November 28, 2011

Representing the ants among the giants

New research from PNNL helps understand methods to capture information about increased cloud brightness in climate models. [Image: Andrew Rakowski]

New research from PNNL helps
understand methods to capture
information about increased
cloud brightness in climate
models.
[Image: Andrew Rakowski]

To describe the effects of tiny aerosols in global climate change, scientists use parameterizations, a technique that lets them represent the particles that can act as seeds for clouds. The question is: which parameterizations should be used in which situations to best represent aerosols and cloud formation? To answer that question, Dr. Steven Ghan at DOE’s Pacific Northwest National Laboratory and his international team evaluated popular parameterizations. They found that the simpler parameterizations worked well under most conditions, but the more complex schemes worked well under a wider variety of conditions.

At the root of this aerosol effect is how the particles become cloud droplets, and how the aerosols brighten the clouds. Brighter clouds scatter sunlight and have a cooling effect on the Earth. Cloud droplet size and number also affect rainfall. Understanding the cooling effect of brighter clouds, and the effect on rainfall, are two important parts of the climate picture.

The team’s conclusions and recommendations were published in the Journal of Advances in Modeling of Earth Systems. The research was funded by the DOE Atmospheric Systems Research Program with support from National Aeronautics and Space Administration and the National Science Foundation.

[Kristin Manke, 509.372.6011,
kristin.manke@pnnl.gov]