Scientists Plot Pollutants’ Path at the Arctic

Scientists Plot Pollutants’ Path at the Arctic

02 April 2008

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The Arctic is a receptacle of the planet’s air pollutants — from forest fires to human-produced carbon dioxide emissions — and a coordinated international effort is geared toward learning more about pollutants’ effects at the top of the globe.

“The pole is this isolated place that receives pollution from all locations,” explained Jim Crawford, tropospheric chemistry program manager at NASA headquarters. So scientists are working to get a clearer picture of the types of pollutants, their pathways and whether they are human or natural in origin, he said.

A broad international effort called POLARCAT — Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols and Transport — incorporates ground stations, airplanes, balloons, ships and satellites to closely study pollutants at the Arctic. Coordinated by Norway, numerous countries are involved including Canada, France, Germany, Russia and the United States.

The spotlight, so to speak, is on Arctic haze — the layers of pollution that tend to linger over the Arctic in the winter and spring months. The POLARCAT campaigns aim to learn more about the makeup of these polluted air masses, seasonal changes, effects on snow and ice covers, and how they impact cloud formations.

Researchers also hope to learn where the pollutants originate. For example, the projects will measure chlorofluorocarbons. That class of chemical compounds has been blamed for reducing the Earth’s protective ozone layer and has been banned in some countries but is still in use in others.

The data collected will be added to Earth science models that help forecast air quality and gauge how the Arctic may respond to future environmental changes.

Crawford and NASA radiation scientist Hal Maring are leading one of the sub-projects, called Arctic Research of the Composition of the Troposphere from Aircraft and Satellites, or ARCTAS.

Under ARCTAS, the United States, France and Germany intend to fly sensor-laden aircraft from Alaska and Canada during three-week periods in April and July. The spring missions will focus on pollution drifting up from northern continents, creating Arctic haze, and the summer flights will take readings when temperatures are warmer and forest fires in northern latitude countries are most active, Crawford said.

The measurements taken during the short-term flights will help validate data from longer-term observations from polar-orbiting satellites.

“It’s the first study that looks at the Arctic atmosphere in understanding climate change and the long-term transport of pollutants,” said Daniel J. Jacob, professor of atmospheric chemistry at Harvard University and an ARCTAS project scientist.

Also in the spring, the National Oceanic and Atmospheric Administration is conducting a research cruise with an eye on pollutants from local sources and ship emissions in an ice-free area of the eastern Arctic — in the Greenland, Norwegian and Barents Seas — in a project with the acronym ICEALOT.

The measurements will serve as a baseline, so scientists will later be able to determine whether there is an increase in pollutants from a potential increase in ship traffic due to the loss of ice cover along the Northern Sea Route and Northwest Passage, according to the agency.

Jacob said the findings from these scientific missions will likely be incorporated into future reports by the Intergovernmental Panel on Climate Change. But the policy implications for the environment are less clear and further down the road.

First, he said, the data will be published in scientific journals, where it will be peer-reviewed, and then it will be distilled into documents for the general public and possible use by policy-makers.

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