Brookhaven Scientists Sample the Skies
“One main goal is to understand how pollutants from the Northeastern U.S. affect climate and air quality as they spread over the North Atlantic Ocean,” said Peter Daum, lead researcher for the Brookhaven/DOE team.
The DOE scientists, funded and coordinated by the Office of Biological and Environmental Research (OBER) within DOE’s Office of Science, focused on evaluating the effects of aerosol pollutants on Earth’s radiation balance and climate forcing for a portion of the study known as the NorthEast Aerosol eXperiment (NEAX).
From July 20 to August 15, 2004, the DOE team launched regional air-sampling flights from Latrobe Airport, located about 25 miles east of Pittsburgh, Pennsylvania. Their aircraft, a G-1 Gulfstream operated by PNNL, carried research-grade instruments developed at both BNL and PNNL. Measurements gathered by additional ground-based instruments, which were deployed by ANL and PNNL scientists, provided complementary data.
“This large multi-agency study is a good example of how organizations with common goals can collaborate, pool resources, and accomplish something that they cannot do by themselves,” said Daum.
Aerosols such as sulfur compounds result from emissions by fossil-fuel-burning power plants and other industrial sources. By themselves, and by affecting the brightness of clouds, they may increase the amount of incoming sunlight that is reflected back into space, thereby exerting a partial cooling effect on Earth’s climate.
“Lack of knowledge regarding how aerosols are formed and distributed
in the atmosphere and how they change the properties of clouds is one of
the key factors preventing more accurate predictions of climate change.”
— Peter Daum
“But because their concentrations are highly variable and because they are removed from the atmosphere fairly quickly, it is difficult to assess these effects and the impact of aerosols on climate without collecting data in the ambient atmosphere,” said Daum.
So the scientists participating in NEAX were particularly interested in aerosol formation and growth in plumes from point sources such as power plants, and in urban plumes with different characteristics. They also conducted air mass scale studies to see how the chemical, microphysical, and optical properties of aerosols evolve as the air mass ages and is transported to the east away from its sources.
Much of the data is still under analysis but it is already apparent that voluntary summertime reductions in power plant emissions are having an effect on the amount of ozone transported from western Pennsylvania to the Northeast. Ultimately, the scientists hope to characterize how much aerosols and aerosol precursors in the Midwest contribute to the aerosol burden over the western North Atlantic Ocean.
“Lack of knowledge regarding how aerosols are formed and distributed in the atmosphere and how they change the properties of clouds is one of the key factors preventing more accurate predictions of climate change,” Daum said.
Findings from this study should help uncloud the climate picture.