The Airborne Antarctic Ozone Experiment (AAOE)

From August to October 1987, the NASA ER-2 and the DC-8 aircraft were flown out of Punta Arenas, Chile, to determine the cause of the Antarctic ozone hole. This was the AAOE mission.

At the time the mission began, the Antarctic ozone hole had been discovered, but its causes were not yet clearly understood. The 1986 NOZE I expedition, which launched balloon-borne instruments from McMurdo station in Antarctica, had provided evidence strongly suggesting that perturbed chlorine chemistry was involved. But there was still no conclusive proof that chlorine was to blame for the ozone hole, and whether the hole was a natural phenomenon having to do with changes in temperature and air circulation, or whether it was caused by chlorine compounds contributed by man-made chemicals, was still a matter of debate.

By fortuitous coincidence, a suite of instruments had been developed for measuring trace gases in the lower stratosphere from the ER-2. These instruments, which measured ozone, water vapor, NOy, and meteorological variables, had just flown during the Stratosphere-Troposphere Exchange Project (STEP). In addition, Dr. James Anderson's group at Harvard University was able to design an adaptation of their balloon-borne instrument to measure chlorine monoxide from the ER-2. With the addition of some other instruments to measure particles from polar stratospheric clouds, a set of 13 instruments was available and ready to take the measurements needed. In addition, seven instruments flew aboard the DC-8, including a laser device which looked up into the stratosphere to measure ozone profiles.

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Some sights from the mission

Here are some pictures taken during the AAOE mission.

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The Official NASA web page for the AAOE experiment is maintained by the Earth Science Division Project Office at NASA Ames Research Center.

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AAOE Investigators

• Project Leadership
  • A. Tuck (NOAA Aeronomy Lab): Project Scientist
  • B. Toon (NASA Ames): Deputy Project Scientist
• ER-2 instruments
  • J. Anderson (Harvard): Multiple axis resonance fluorescence chemical conversion detector for ClO and BrO
  • K.R. Chan NASA Ames): ER-2 meteorological measurement system
  • D. Fahey (NOAA Aeronomy Lab): NOy detector
  • G. Ferry (NASA Ames): Aerosol and cloud spectrometers
  • B. Gandrud (NCAR): Multi filter sampler
  • B. Gary (NASA JPL): Microwave temperature profiler
  • L. Heidt (NCAR) & J. Vedder (NASA Ames): Whole air sampler
  • K. Kelly (NOAA Aeronomy Lab): Lyman alpha hygrometer
  • M. Lowenstein (NASA Ames): Airborne tunable laser absorption spectrometer
  • V. Oberbeck (NASA AMes): Particle chemistry impactor experiment
  • M. Proffitt (NOAA Aeronomy Lab): Dual-beam UV-absorption ozone photometer
  • W. Starr (NASA Ames): Ames ultraviolet ozone photometer
  • J. C. Wilson (U. Denver): Condensation nucleus counter
• DC-8 instruments
  • E. Browell (NASA Langley): ozone and aerosol DIAL system
  • C. Farmer (NASA JPL): Mark IV interferometer
  • G. Gregory (NASA Langley): Chemiluminescent ozone detector
  • L. Heidt (NCAR) & J. Vedder (NASA Ames): Whole air sampler
  • K. Kelly (NOAA Aeronomy Lab): Lyman alpha hygrometer
  • B. Mankin and M. Coffey (NCAR): Fourier transform spectrometer
  • A. Wahner & R. Jakoubek (NOAA Aeronomy Lab): NOAA Near UV atmospheric absorption experiment
• Satellite data team
  • D. Cariolle (Centre Nationale de Recherches Météorologiques): TOVS, HIRS 2 analyses
  • A. Krueger (NASA Goddard): Total Ozone Mapping Spectrometer (TOMS)
  • P. McCormkick (NASA Langley): Stratospheric Aerosol Measurement (SAM) II
• Theory team
  • D. Hartmann (U. Washington)
  • R. Jones (UK Met Office)
  • J. Rodriguez (AER, Inc.)
  • M. Schoeberl (NASA Goddard)
  • N. Sze (AER, Inc.)

What this mission accomplished

AAOE determined that the cause of the Antarctic ozone hole as indeed chlorine chemistry. Large quantities of chlorine monoxide were found which were co-located with areas of ozone depletion. The aerosol data gathered was consistent with processing on polar stratospheric clouds. But the theories which said that it was a natural phenomenon due to atmospheric dynamics were found to be inconsistent with the new data.

The AAOE results were published in two special issues of the Journal of Geophysical Research: volume 94, number D9, August 30, 1989; and volume 94, number D14, November 30, 1989.