Articles | Volume 5, issue 5
Atmos. Meas. Tech., 5, 927–953, 2012
Atmos. Meas. Tech., 5, 927–953, 2012

Research article 04 May 2012

Research article | 04 May 2012

Validation of ACE and OSIRIS ozone and NO2 measurements using ground-based instruments at 80° N

C. Adams1, K. Strong1, R. L. Batchelor1,*, P. F. Bernath2,3,4, S. Brohede5, C. Boone2, D. Degenstein6, W. H. Daffer7, J. R. Drummond1,8, P. F. Fogal1, E. Farahani1, C. Fayt9, A. Fraser1,**, F. Goutail10, F. Hendrick9, F. Kolonjari1, R. Lindenmaier1, G. Manney7,11, C. T. McElroy12,13, C. A. McLinden13, J. Mendonca1, J.-H. Park1, B. Pavlovic1, A. Pazmino10, C. Roth6, V. Savastiouk14, K. A. Walker1,2, D. Weaver1, and X. Zhao1 C. Adams et al.
  • 1Department of Physics, University of Toronto, Toronto, Canada
  • 2Department of Chemistry, University of Waterloo, Waterloo, Canada
  • 3Department of Chemistry, University of York, York, UK
  • 4Department of Chemistry & Biochemistry, Old Dominion University, Norfolk, VA, USA
  • 5Global Environmental Measurements and Modelling, Department of Earth and Space Sciences, Chalmers University of Technology, 412 96 Göteborg, Sweden
  • 6University of Saskatchewan, Saskatoon, Saskatchewan, Canada
  • 7Jet Propulsion Laboratory, California Insititute of Technology, Pasadena, USA
  • 8Department of Physics and Atmospheric Sciences, Dalhousie University, Halifax, Canada
  • 9Institut d'Aeronomie Spatiale de Belgique (IASB-BIRA), Brussels, Belgium
  • 10Versailles St-Quentin, CNRS/INSU, LATMOS-IPSL, 78280 Guyancourt, France
  • 11New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA
  • 12York University, Toronto, Ontario, Canada
  • 13Environment Canada, Downsview, Ontario, Canada
  • 14Full Spectrum Science Inc., Toronto, Ontario, Canada
  • *now at: Atmospheric Chemistry Division, NCAR Earth Systems Laboratory, Boulder, Colorado, USA
  • **now at: School of GeoSciences, University of Edinburgh, Edinburgh, UK

Abstract. The Optical Spectrograph and Infra-Red Imager System (OSIRIS) and the Atmospheric Chemistry Experiment (ACE) have been taking measurements from space since 2001 and 2003, respectively. This paper presents intercomparisons between ozone and NO2 measured by the ACE and OSIRIS satellite instruments and by ground-based instruments at the Polar Environment Atmospheric Research Laboratory (PEARL), which is located at Eureka, Canada (80° N, 86° W) and is operated by the Canadian Network for the Detection of Atmospheric Change (CANDAC). The ground-based instruments included in this study are four zenith-sky differential optical absorption spectroscopy (DOAS) instruments, one Bruker Fourier transform infrared spectrometer (FTIR) and four Brewer spectrophotometers. Ozone total columns measured by the DOAS instruments were retrieved using new Network for the Detection of Atmospheric Composition Change (NDACC) guidelines and agree to within 3.2%. The DOAS ozone columns agree with the Brewer spectrophotometers with mean relative differences that are smaller than 1.5%. This suggests that for these instruments the new NDACC data guidelines were successful in producing a homogenous and accurate ozone dataset at 80° N. Satellite 14–52 km ozone and 17–40 km NO2 partial columns within 500 km of PEARL were calculated for ACE-FTS Version 2.2 (v2.2) plus updates, ACE-FTS v3.0, ACE-MAESTRO (Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) v1.2 and OSIRIS SaskMART v5.0x ozone and Optimal Estimation v3.0 NO2 data products. The new ACE-FTS v3.0 and the validated ACE-FTS v2.2 partial columns are nearly identical, with mean relative differences of 0.0 ± 0.2% and −0.2 ± 0.1% for v2.2 minus v3.0 ozone and NO2, respectively. Ozone columns were constructed from 14–52 km satellite and 0–14 km ozonesonde partial columns and compared with the ground-based total column measurements. The satellite-plus-sonde measurements agree with the ground-based ozone total columns with mean relative differences of 0.1–7.3%. For NO2, partial columns from 17 km upward were scaled to noon using a photochemical model. Mean relative differences between OSIRIS, ACE-FTS and ground-based NO2 measurements do not exceed 20%. ACE-MAESTRO measures more NO2 than the other instruments, with mean relative differences of 25–52%. Seasonal variation in the differences between NO2 partial columns is observed, suggesting that there are systematic errors in the measurements and/or the photochemical model corrections. For ozone spring-time measurements, additional coincidence criteria based on stratospheric temperature and the location of the polar vortex were found to improve agreement between some of the instruments. For ACE-FTS v2.2 minus Bruker FTIR, the 2007–2009 spring-time mean relative difference improved from −5.0 ± 0.4% to −3.1 ± 0.8% with the dynamical selection criteria. This was the largest improvement, likely because both instruments measure direct sunlight and therefore have well-characterized lines-of-sight compared with scattered sunlight measurements. For NO2, the addition of a ±1° latitude coincidence criterion improved spring-time intercomparison results, likely due to the sharp latitudinal gradient of NO2 during polar sunrise. The differences between satellite and ground-based measurements do not show any obvious trends over the missions, indicating that both the ACE and OSIRIS instruments continue to perform well.