Aerosols are microscopic particles—like dust, pollen and soot—that ubiquitously float around in our atmosphere. Despite their tiny stature, these particles can have a huge impact on human health, climate and the environment. So scientists from the Pacific Northwest National Laboratory (PNNL), Colorado State University and the California Air Resources Board have set out to characterize the roles of various particles as atmospheric change agents on a regional scale.
For the first time ever, these researchers have characterized the relative, direct influence of different aerosol species on seasonal atmospheric warming and cooling over California using supercomputers at the Department of Energy’s National Energy Research Scientific Computing Center (NERSC) and at PNNL. The scientists found that aerosols have a net cooling effect on California’s atmosphere, but individual species contribute differently. While sulfates contributed the most to cooling, black carbon particles, or soot, were responsible for up to 95 percent of countervailing warming.
“With a better understanding of how each particle affects the atmosphere, we can assess the success of regional emissions controls of anthropogenic, or human-caused particles,” says Chun Zhao, a PNNL climate scientist and lead author of a paper published the Journal of Geophysical Research.
Direct effects of aerosols
Earth’s climate is driven by radiation provided by the sun, but not all of it reaches our planet’s surface. A quarter of this energy is actually reflected back into space by aerosols laced in clouds, or floating around in the atmosphere. This effect leads to atmospheric cooling. However, some aerosols can cause atmospheric warming by absorbing solar radiation. Because aerosols comprise such a broad collection of particles, with vastly different properties, the degree to which each absorbs or deflects energy varies.
Read more at: Phys.org