NSF Grant Funds Research of Earth’s Atmospheric Cooling Processes
August 3, 2007
The National Science Foundation has awarded a grant to Drexel University chemistry professor Dr. Alan Bandy to conduct research on Earth’s cooling system.
According to Bandy, the principal investigator in the Pacific Atmospheric Sulfur Experiment (PASE), the temperature of Earth’s atmosphere is determined by processes that heat it—such as absorption of Earth’s radiation by certain gases—and by processes that cool it –such as reflection of the sun’s radiation from Earth’s surface, aerosol and clouds.
“Although processes that cool and heat the atmosphere are equally important, the cooling processes, on which PASE is focused, are much less well known than the heating processes,” said Bandy. “This phenomenon occurs because heating terms involve gases that are relatively easy to deal with whereas cooling terms largely involve condensed phases such as Earth’s surface, aerosols and clouds, which are very complex and thus difficult to study.”
Bandy’s experiment is airborne and will be conducted at a low altitude (30 to 2000m) about 200 km east of Christmas Island (Kiritimas). Bandy and a team of 35 researchers from the University of Hawaii, University of Rhode Island, Georgia Tech, National Center for Atmospheric Research, Desert Research Institute, and University of California-Davis will conduct the experiment aboard a NCAR C130. The team is currently at Christmas Island where the researchers will remain for about six weeks.
PASE will focus on the clouds in the marine atmosphere, which appear as floating cotton balls when one flies over the ocean. The experiment will also concentrate on the cloud-free region under these clouds because this air is eventually transported upward through the clouds carrying the precursors of chemical process that occur in the cloud
“These are the processes we believe control cloud reflectivity and thus the cooling potential of the cloud,” said Bandy. “This is the first in a series of experiments that will focus on progressively more complex systems and eventually lead to an acceptable model of the cooling these clouds produce.”
The precursors of sulfur compounds involved in the important chemical process in the cloud are derived from the ocean, according to Bandy and his team. Sea salt and of dimethyl sulfide are transported to the atmosphere from the ocean surface.
“It is these compounds that are the driving force for this chemistry occurring in the clouds, although many other chemicals common to all clean air are involved and are very important,” said Bandy.
The author of more than 120 publications, Bandy has been a principal investigator of numerous NSF and NASA missions. His research focuses on the development of methods and instrumentation for determining trace gaseous species in the atmosphere using mass spectrometry; the chemistry of atmospheric sulfur, nitrogen and halogens; the nucleation and growth of new atmospheric particles; the condensation nuclei formation from trace gas precursors in the marine atmosphere and their impact on clouds and climate; and modeling of solution and gas phase conversion processes.
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