The Airborne Arctic Stratospheric Expedition II (AASE)

From October 1991 through March 1992, the NASA ER-2 and the DC-8 aircraft were flown out of Fairbanks, Alaska, and Bangor, Maine, to examine the evolution of the chemistry of the stratospheric polar vortex over the course of the winter. This was AASE II.

AASE II began about two and a half years after the Airborne Arctic Stratospheric Experiment (AASE), which determined that the chlorine chemistry in the Northern Hemisphere polar winter stratosphere was indeed perturbed, similar to the situation in the Southern Hemisphere winter. This mission was designed to measure chemical and meteorological variables as the Northern polar vortex--the ring of winds which circles the pole in winter--evolved through the season.

The first deployment was out of Fairbanks, Alaska, in October 1991. The ER-2 flew north to the pole to survey the beginnings of the polar vortex. Subsequent deployments were staged from Bangor, Maine, for two-week periods spaced about two weeks apart from November 1991 through March 1992. Most flights were north towards the polar vortex, but a few went south towards the tropics to survey aerosols injected into the stratosphere by the eruption of the Pinatubo volcano in June 1991.

The ER-2 was joined by the NASA DC-8 beginning with the January deployment. The DC-8, which has a much longer range than the ER-2, flew circuits from NASA Ames Research Center in Moffett Field, California, to Fairbanks, Alaska, to Stavanger, Norway, to Bangor, Maine, and then back to NASA Ames.

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Some sights from the mission

Here are some pictures taken during the AASE II mission.

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

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AASE II Investigators

• Project Leadership
  • J. Anderson (Harvard): Project Scientist
  • B. Toon (NASA Ames): DC-8 Flight Scientist
  • S. Wegener (NASA Ames): ER-2 Science Coordinator, Instrument Manager, & Project Control Officer
• ER-2 instruments
  • K.R. Chan (NASA Ames): ER-2 meteorological measurement system
  • J. Elkins (NOAA Climate Monitoring & Diagnostics Lab) and D. Fahey (NOAA Aeronomy Lab): Fast Response CFC-11: Airborne Chromatograph for Atmospheric Trace Species (ACATS)
  • D. Fahey (NOAA Aeronomy Lab): Reactive nitrogen
  • G. Ferry (NASA Ames) and J. C. Wilson (U. Denver): Focussed Passive Cavity Aerosol Spectrometer
  • G. Ferry (NASA Ames): FSSP-3000 Aerosol Spectrometer
  • B. Gary (NASA Ames): 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
  • M. Proffitt (NOAA Aeronomy Lab): Dual-beam UV-absorption ozone photometer
  • R. Pueschel (NASA Ames): Particle chemistry impactor experiment
  • D. Toohey (Harvard): Multiple axis resonance fluorescence chemical conversion detector for ClO and BrO
  • C. Webster (NASA JPL): Aircraft laser infrared absorption spectrometer
  • J. C. Wilson (U. Denver): Condensation nucleus counter
• DC-8 instruments
  • D. Blank and F. S. Rowland (U. California Irvine): Halocarbon and nonmethane hydrocarbon grab samples
  • E. Browell (NASA Langley): ozone and aerosol DIAL system
  • B. Gary (NASA Ames): Miscrowave temperature profiler
  • K. Kelly (NOAA Aeronomy Lab): Lyman alpha hygrometer
  • B. Mankin and M. Coffey (NCAR): Fourier transform spectrometer
  • R. Pueschel (NASA Ames): Ames airborne autotracking sun photometer
  • R. Pueschel (NASA Ames): Optical particle counters and impactors
  • B. Ridley, A. Weinheimer, J. Wakaga (NCAR): In-situ NO, NOy, O3
  • G. Sachse and B. Anderson (NASA Langley): Diode laser differential absorption sensor for the measurement of CO, CH4, and N2O/NDIR analyser for CO2 measurements
  • G. Toon (NASA JPL): Mark IV Interferometer
  • W. Traub (Harvard-Smithsonian Center for Astrophysics): FIRS-2 Emission Spectrometer
  • F. Valero (NASA Ames): Narrow spectral bandpass, narrow field-of-view multiple spectral channels infrared radiance radiometer
• Meteorological support
  • M. Schoeberl (NASA Goddard): Meteorological analyses for AASE II

What this mission accomplished

Here is the end-of-mission statement drafted by the mission participants at its close in March 1992.

AASE II results were published in special issues of Science, vol. 261, no. 5125, and Geophysical Research Letters, vol. 20, no. 22.