DURHAM, N.H. -- University of New Hampshire scientists are part of a $20 million NASA mission to better understand how pollution from eastern
Asia impacts the composition of the global atmosphere.
The mission, called TRACE-P (TRansport and Chemical Evolution over the Pacific), uses two NASA aircraft operating out of Yokota Air Force Base near Tokyo, Japan, and Hong Kong. The aircraft payloads include a suite of instruments to measure concentrations of greenhouse gases, ozone-forming photochemical oxidants and aerosols. It is the follow-up to two previous missions that the university researchers were involved with in 1991 and 1994.
Asia, due to rapid industrialization over the past decade, is now a major source of pollution emissions, rivaling both the United States and Europe. NASA is especially concerned because this pollution has a major impact on the chemistry over the Pacific, and eventually impacts the U.S. west coast and possibly the large-scale northern hemisphere. "The rapid industrialization now taking place in Asia is of compelling interest," says Robert Talbot, research professor at the University of New Hampshire's Institute for the Study of Earth, Oceans, and Space. "Energy use in eastern Asia has increased dramatically over the past decade. The combustion of fossil fuels emits gases which are known to have a detrimental effect on human health, agricultural production and climate. And aerosols, which lead to cloud formation and cooling, play an integral role in global warming."
Talbot and his colleagues, who include fellow UNH scientists Jack Dibb, Eric Scheur and Gary Seid, are part of the research team aboard the NASA Dryden DC-8 research aircraft. It will fly as high as 41,000 feet, taking air chemistry measurements over a period of time from March through April. Spring is the season of maximum Asian outflow over the Pacific, and also a time of high ozone formation due to increasing solar radiation. More than 30 other researchers from such institutions as the University of California, Irvine, Massachusetts Institute of Technology, Harvard University, NASA Langley Research Center, and the National Center for Atmospheric Research are working on TRACE-P.
The mission began at the Edward Air Force Base in Dryden, Calif., and travels to Hawaii, Guam, Hong Kong, Taiwan, Okinawa and Japan. The research teams will log 163 flight hours, taking precise measurements to build a picture of the overall chemistry over the Pacific. They'll be determining the pathway of these gases and aerosols as they flow from eastern Asia to the U.S. west coast, and they'll be trying to better understand how these chemicals change over time as they travel.
The UNH team is measuring nitric acid, sulfur dioxide, and aerosol sulfate from the DC-8 aircraft. "The sulfur species are particularly key to the TRACE-P mission, as they are important tracers of fossil fuel combustion," says Dibb. "Combustion of coal in Asia is known to be especially high in sulfur emissions."
UNH scientists are taking measurements before the sun rises, as it comes up, and after it has risen to better understand the photochemical processes taking place.
"We're also measuring vertical cross sections to look for variability and at what altitudes the pollution is leaving the continent, as well as measuring parallel to the coast and further out for long-range transport," says Talbot. "Our goal is to find out how these gases and aerosoles are transported across the Pacific and how they evolve chemically over time."
The UNH team is using custom-fabricated instrumentation and scientific methods that took decades to develop. They have an air inlet on the side of the aircraft that brings in about 3,000 liters of highly reactive gas a minute, and two aerosol-detecting probes on the top of the plane. Due to the nature of airborne research, intense pressure is on everyone to have things working on schedule. Trouble-shooting skills are highly valued.
"It's an incredibly complex process to measure these trace gases without disturbing them," Talbot says.
Despite the stress-filled, 18-hour days, he says the mission "is a unique opportunity to observe the atmospheric impact of what is essentially an ongoing major industrial revolution. It will help us better understand the impact of natural and human activities on global chemistry, and provide valuable information to policy makers focused on controlling these harmful emissions."