Ozone measurements during the Airborne Polar Experiment : Aircraft instrument validation, isentropic trends, and hemispheric fields prior to the 1997 Arctic ozone depletion

摘要: The first deployment of the ECOC electro chemical ozone cell (ECOC) instrument onboard high-altitude research aircraft, Geophysica M-55, took place from Rovaniemi, northern Finland, between December 23, 1996, and January 14, 1997. data were compared against contemporaneous a network balloon-borne sondes. comparison was carried out in potential vorticity-potential temperature (PV, Θ) coordinates, using meteorological analyses European Centre for Medium-Range Forecasts. showed that mixing ratios measured by are lower than those ozonesonde small but statistically significant bias (−5.7 ± 2.8)% at cruising altitudes 15 to 19 km. After establishing removing average bias, analyzed together follow development distributions early winter Arctic stratosphere. analysis no evidence depletion is, 435 490 K. absence is agreement with polar statospheric cloud (PSC) observations, which PSCs aircraft altitudes, although 5 onwards, observed above altitudes. Results three-dimensional transport model reproduce basic features reconstructed fields. However, does not capture increase during campaign, due weak modeled vertical gradients, indicates about 3% inside vortex 480 K mid January.