Results from the 1995 Stratospheric Ozone Profile Intercomparison at MaunaLoa

In August 1995, multiple instruments that measure the stratospheric ozone v ertical distribution were intercompared at the Mauna Loa Observatory, Hawai i, under the auspices of the Network for the Detection of Stratospheric Cha nge. The instruments included two UV lidar systems, one from the Jet Propul sion Laboratory and the other from Goddard Space Flight Center, electrochem ical concentration cell balloon sondes, a ground-based microwave instrument , Dobson-based Umkehr measurements, and a new ground-based Fourier transfor m infrared instrument. The Microwave Limb Sounder instrument on the Upper A tmosphere Research Satellite provided correlative profiles of ozone, and th ere was one close overpass of the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument. The results show that much better consistency amon g instruments is being achieved than even a few years ago, usually to withi n the instrument uncertainties. The different measurement techniques in thi s comparison agree to within +/-10% at almost all altitudes, and in the 20- 45 km region most agreed within +/-5%. The results show that the current ge neration of lidars is capable of accurate measurement of the ozone profile to a maximum altitude of 50 km. SAGE II agreed well with both lidar and bal loon sonde down to at least 17 km. The ground-based microwave measurement a greed with other measurements from 22 km to above 50 km. One minor source o f disagreement continues to be the pressure-altitude conversion needed to c ompare a measurement of ozone density versus altitude with a measurement of ozone mixing ratio versus pressure.