| NOAA 2000-R619 FOR IMMEDIATE RELEASE Contact: Barbara McGehan 12/28/00 |
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TO DETERMINE CENTURY'S AIR QUALITY A team of university and NOAA scientists will search the snowpack for 100 year- old air samples at the South Pole this January, to investigate what the air quality was like during the last century. The pockets of air trapped in the snowpack will provide scientists with a historical record of gases that were present in the atmosphere during this period. Researchers will then be able to analyze this record for clues to how human activity has influenced atmospheric processes. With support from the National Science Foundation and NOAA, the six investigators from Bowdoin College in Maine, NOAA's Climate Monitoring and Diagnostics Laboratory, the University of Wisconsin, and Princeton University, will draw air from the snowpack at incremental depths, stopping at about 120 meters, at which point the snow turns to ice. They will collect the air samples and return them for initial analyses to government and university labs in the U.S., New Zealand and Australia. "It is important that we get these air samples now,"said Jim Butler of NOAA. "Each year we delay, we lose a year of history, as the snow turns to ice at the bottom of the hole. Just a few years from now, we will not be able to obtain air samples that span the entire 20th century, a time of rapid population, agricultural, and industrial growth." Recent studies by the same research team published in the journal Nature in1996 and in 1999, indicated that the composition of the atmosphere has changed dramatically over the past 100 years, presumably because of human activities. These previous studies demonstrated the feasibility of obtaining representative atmospheric histories from air trapped in the snowpack that sits atop the polar ice sheets. Although longer histories of some gases can be obtained from ice cores, the gas samples are tiny. Current analytical techniques do not allow for accurate measurement of trace gases in these minute amounts. In the snowpack, however, the amount of air is essentially unlimited. This allows for high-precision measurement of gases that occur in very low concentrations in the atmosphere. According to Mark Battle of Bowdoin College and leader of the expedition, "One of the things we learned from our previous work was just how good these samples can be. Now we're in a position to reconstruct the histories of some gases with a precision we never imagined six years ago." Large amounts of the old air will be stored at the NOAA facility in Boulder, Colo., in what's known as an air archive. This archive will be available for future analyses, to answer questions that haven't even been thought of yet, and with techniques yet to be developed. Due to the scientific requirements of the project, the field team will be camping near the South Pole while they drill, instead of residing inside the permanent facility at the South Pole. "We'll be extracting air from undisturbed
snowpack, so we need to be located far from other activities
going on at the South Pole," Butler said. Temperatures at
the South Pole in January range from -11 to -40 degrees Fahrenheit
and windspeeds average about 11 miles per hour. |