This collaborative campaign will measure ozone and other atmospheric gases using satellites, airplanes, heavy-lift and small balloons, and ground-based instruments. From November 1999 through March 2000, researchers will examine the processes that control ozone amounts during the Arctic winter at mid to high latitudes.

"The combined campaign will provide an immense new body of information about the Arctic stratosphere," said program scientist Dr. Michael Kurylo, NASA Headquarters, Washington, DC. "Our understanding of the Earth's ozone will be greatly enhanced by this research."

The Earth's ozone layer protects life below from the harmful ultraviolet radiation coming from the Sun. This radiation can damage DNA molecules, thereby leading to the formation of skin cancers.

Very low levels of ozone were observed over the Arctic in several winters during the 1990s, raising concerns that an Arctic ozone hole might be forming.

Recent modeling work has suggested that greenhouse gas warming might lead to larger-than-expected Arctic ozone losses in the future and also may delay the expected recovery of the ozone layer globally.

For the first time, measurements of stratospheric composition over the Arctic will be made using a large suite of instruments aboard several European aircraft, as well as on NASA's DC-8 and ER-2, based at Dryden Flight Research Center, Edwards, Calif. Balloons, carrying payloads ranging from several pounds to several thousand pounds and ground-based instruments will also take atmospheric readings.

"Handling all the hardware and coordinating the personnel, aircraft, balloons, and ground observations involved in the campaign is an immense challenge," said project manager Michael Craig of NASA's Ames Research Center, Moffett Field, Calif. More than 350 scientists, technicians and support workers are involved in the experiment.

More than 15 years ago, scientists detected an "ozone hole" over the South Pole that has reappeared each year during the Southern Hemisphere winter and spring. Researchers from around the world recognized more than a decade ago that the ozone depletion is caused primarily by man-made chlorine and bromine compounds.

The chlorine compounds have been produced for use as refrigerants, aerosol sprays, solvents and foam blowing agents, while bromine-containing halons have been used in fire extinguishing. Man-made production of chlorofluorocarbons ceased in 1996 in developed countries under the terms of the Montreal Protocol and its Amendments.

Scientists also will take measurements that will be useful in validating data from an instrument called SAGE III aboard the Russian Meteor-3 satellite. Once the spacecraft is launched, SAGE III will measure the vertical structure of aerosols, ozone, water vapor and other trace gases in the Arctic upper troposphere and stratosphere. NASA's Langley Research Center, Hampton, Va., manages the SAGE III project.

Project scientists will be based above the Arctic Circle at the airport in Kiruna, Sweden. "Arena Arctica," a large hangar especially built for research, will house the aircraft and many of the scientific instruments. Balloons will be launched from Esrange, a balloon and rocket launch facility near Kiruna. Wintertime conditions can be very severe, with temperatures falling below 50 degrees below zero Fahrenheit.

The NASA-sponsored SAGE III Ozone Loss and Validation Experiment (SOLVE) is being conducted jointly with the European Commission-sponsored Third European Stratospheric Experiment on Ozone (THESEO 2000).