SCIENTISTS BRAVE BRUTAL ELEMENTS ON TOP OF THE WORLD TO STUDY OZONE LAYER
Feb. 18, 2005 ó Doing cutting-edge science in one of Earth's most challenging environments requires meticulous planning and years of experience and education, but sometimes a smidgen of serendipity helps. That kind of "just-in-time" good fortune may well allow NOAA scientists to study an unusual thinning of the Arctic ozone layer that has started as the sunlight returns to the Arctic. The phenomenon is caused by extremely low Arctic temperatures this year. It will last only a matter of weeks. (Click image for larger view of the Greenland Environmental Observatory at Summit in the Arctic where scientists work to monitor the ozone layer. Click here for high resolution version, which is a large file. Please credit NOAA/NSF.)
The data that scientists expect to gather at the Greenland Environmental Observatory at Summit (GEOSummit), which is strategically located under the area of the sky where the ozone is thinning, could provide them with important insights into how the atmosphere reacts to extremes in temperatures, even as levels of ozone-depleting chemicals in the atmosphere decline in the coming years.
"One key question right now is how the ozone layer will behave as the chlorine in the atmosphere decays away under the Montreal Protocol to understand what we need to know about the variability that can happen in a cold year like this one," said Susan Solomon, a senior scientist at the NOAA Aeronomy Laboratory in Boulder, Colo.
Solomon was the leading scientist in identifying the cause of the Antarctic ozone hole.
"This is the period of peak vulnerability of the ozone layer since chlorine is near its maximum right now," she said. "Under full compliance with the Montreal Protocol, the ozone layer will slowly heal in coming decades, but we need to know how vulnerable the Arctic really is—whether it could look more like the Antarctic in a really exceptional year. And, this could be the year that we see it at its worst." (Click image for larger view of the Greenland Environmental Observatory at Summit in the Arctic where scientists work to monitor the ozone layer. Click here for high resolution version, which is a large file. Please credit NOAA/NSF.)
Dave Hofmann, the director of the NOAA Climate Monitoring and Diagnostics Laboratory in Boulder, Colo., and also a veteran of Antarctic ozone hole studies, called the opportunity to study the Arctic ozone phenomenon an exciting historic parallel to the scientific work that pinpointed the significance of ozone depletion in Antarctica.
"This is so reminiscent of 1986 when Susan Solomon and I and a group of scientists made a decision to fly into McMurdo Station in Antarctica in the middle of austral winter with only a few months to prepare for the expedition," he recalled. "It was called the 'National Ozone Expedition,' and it basically nailed CFCs as the cause of the Antarctic ozone hole. Exciting times!"
He added that in the Arctic study "a related question is how other greenhouse gases—especially carbon dioxide—could affect the stratosphere. It's important to understand how changing temperatures, and variable dynamical conditions that could change with global warming, affect the Arctic ozone layer."
capitalize on this opportunity, this week (week of Feb. 15) Jason Seifert,
a NOAA Corps officer, will
leave for a remote scientific station atop the Greenland ice cap, carrying
with him a spectrometer to measure the chemical reaction that is thinning
the protective ozone layer. (Click image for larger view of
the propeller-driven De Havilland Twin Otter aircraft used for the flights
up to the Greenland Environmental Observatory at Summit. Click
here for high resolution version, which is a large file. Please
Seifert will join Andrew Clarke, a scientist with the Cooperative Institute for Research in Environmental Sciences, or CIRES, a joint institute of the University of Colorado at Boulder and NOAA. Clarke arrived at Summit on Feb. 10 and almost immediately sent up the first of what could be as many as 20 ozonesondes—lightweight balloon-borne instruments that sample the chemistry of the upper atmosphere.
Hofmann pioneered the use of ozonesondes in Antarctica 20 years ago.
During the summer in the Southern Hemisphere, Clarke was conducting ozone and other related measurements at the NOAA South Pole Observatory in Antarctica. He had just returned from the southernmost continent when the opportunity to study the Arctic ozone phenomenon presented itself.
He was able to continue his northern trajectory from Antarctica on to Summit only because the rigorous medical clearance required for Antarctic service qualified him to fly immediately to the remote station at the opposite end of the globe.
Although aware it was occurring, less than a week ago, no one expected the opportunity to study the ozone depletion as it occurs to arise. A crew of four, including two science technicians, mans the station year-round, and flights are limited to twice during the winter, one in November and another in February. (Click image for larger view of Andrew Clarke, a scientist with the Cooperative Institute for Research in Environmental Sciences, or CIRES, who during the summer in the Southern Hemisphere was conducting ozone and other related measurements at the NOAA South Pole Observatory in Antarctica. Click here for high resolution version, which is a large file. Please credit NOAA/NSF.)
However, coordination among NOAA-funded entities and other federal agencies such as NSF, as well as VECO Polar resources, of Littleton, Colo., NSF's Arctic logistics coordinator, as well as a little good fortune, may well provide scientists with a wealth of data—both from atmospheric sampling and ground-based instruments—that otherwise might have been missed.
Having Seifert hand-carry the spectrometer, for example, also will help to bring all the elements of the experiment together in a timely fashion. Shipping it might have required lengthy delays in customs and other formalities that would have caused the researchers to miss the Summit flights, said Russell C. Schnell, the director of observatory and global network operations at the NOAA CMDL.
"Everything just happened to click," he said. "We didn't think we'd able to get it all in place, but it looks as though we are going to make it happen."
Seifert will return to the U.S. on Feb. 18 on the last flight out of Summit until the New York Air National Guard's ski-equipped LC-130 "Hercules" aircraft begin their normal seasonal operations. He will return to Summit in April as science officer for the summer research season.
Clarke will stay on the ground at Summit, braving the minus 50.8 degrees Fahrenheit (minus 46 degrees Celsius) weather to launch ozonesondes for the next two months. (Click image for larger view of the Greenland Environmental Observatory at Summit in the Arctic where scientists work to monitor the ozone layer. Click here for high resolution version, which is a large file. Please credit NOAA/NSF.)
The ozone thinning is unusual because the Arctic stratosphere rarely gets as cold as the stratosphere in Antarctica, where air temperatures regularly fall below minus 112 degrees Fahrenheit (minus 80 degrees Celsius), but this year, the atmosphere above the Arctic is the coldest it has been in 50 years.
The unusual cold is causing polar stratospheric clouds to form in a vortex that is created in late autumn by westerly circulating winds in the atmosphere.
The vortex isolates the air in the center from the rest of the atmosphere and causes the temperature to drop precipitously. Because there is no heat from the sun during the long polar night, the air becomes even colder.
When the temperature falls as lows as minus 112 degrees Fahrenheit (minus 80 degrees Celsius), polar stratospheric clouds form. These clouds are chemically unlike the normal clouds of water vapor that form closer to the Earth's surface and they change the air chemistry in the vortex.
This chemical change transforms chlorine from man-made chemicals called chlorofluorocarbons, or CFCs, into a form that breaks down the ozone, a process that is triggered in the spring as sunlight begins to return to the Arctic.
The breakdown of the ozone allows higher levels of ultraviolet radiation from the sun to reach the Earth's surface. Unlike the better-known so-called "Ozone Hole" over Antarctica—which affects the largely unpopulated continent—the radiation pouring through the Arctic ozone hole could have potentially serious health effects on large human populations in Scandinavia and other Arctic countries.
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