Fast Airborne Ozone Measurements

FAIRO onboard Research Aircraft HALO

FAIRO is fully custom-made instrument that combines two measurement techniques:

  • 2-channel UV photometry based on the absorption of UV light by O3
  • Solid-state chemiluminescence detection based on the chemiluminescence (light emission) of O3 at the surface of an organic dye adsorbed on dry silica gel

The strengths of FAIRO are:

  • Compact (19” system, height: 13.5 cm) and light-weight (14 kg)
  • Fully automated
  • Both detectors work at the physical limit, that is, are quantum-noise limited
  • High-accuracy (precision: ~0.1 ppb) and high speed (10 Hz), and thus a factor of >10 more precise and >20 faster than commercial instruments

FAIRO is operated as of 2005 on passenger aircraft and as of 2012 during ~20 research campaigns on board the research aircraft HALO and on two US research aircraft.

Ozone cross section during a flight in March 2007 from China to Germany at 10-12 km. Red: uv photometer (time resolution: 4 s) and Blue: chemiluminescence detector (here smoothed to 1 s time resolution). Green line: chemical tropopause. The variability at ~2100 km is real atmospheric noise, see sub-graph. In spite of constant flight altitude, the aircraft crosses the tropopause many time (>110 ppb stratospheric air), which indicates the extreme dynamical variability of this flight.