Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 5.414
IF5.414
IF 5-year value: 5.958
IF 5-year
5.958
CiteScore value: 9.7
CiteScore
9.7
SNIP value: 1.517
SNIP1.517
IPP value: 5.61
IPP5.61
SJR value: 2.601
SJR2.601
Scimago H <br class='widget-line-break'>index value: 191
Scimago H
index
191
h5-index value: 89
h5-index89
Volume 9, issue 14
Atmos. Chem. Phys., 9, 5343–5369, 2009
https://doi.org/10.5194/acp-9-5343-2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.
Atmos. Chem. Phys., 9, 5343–5369, 2009
https://doi.org/10.5194/acp-9-5343-2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.

  29 Jul 2009

29 Jul 2009

Long-term changes in UT/LS ozone between the late 1970s and the 1990s deduced from the GASP and MOZAIC aircraft programs and from ozonesondes

C. Schnadt Poberaj1, J. Staehelin1, D. Brunner2, V. Thouret3, H. De Backer4, and R. Stübi5 C. Schnadt Poberaj et al.
  • 1Institute for Atmospheric and Climate Science, ETH Zürich, Switzerland
  • 2Laboratory for Air Pollution/Environmental Technology, Empa, Dübendorf, Switzerland
  • 3Laboratoire d'Aérologie, Université de Toulouse, CNRS, Toulouse, France
  • 4Royal Meteorological Institute of Belgium (KMI-IRM), Brussels, Belgium
  • 5Federal Office of Meteorology and Climatology MeteoSwiss, Aerological Station, Payerne, Switzerland

Abstract. We present ozone measurements of the Global Atmospheric Sampling Program (GASP) performed from four commercial and one research aircraft in the late 1970s to compare them with respective measurements of the ongoing MOZAIC project. Multi-annual averages of UT/LS ozone were built using the aircraft data sets (1975–1979 and 1994–2001), and long-term changes between the 1970s and 1990s were derived by comparison. The data were binned relative to the dynamical tropopause to separate between UT and LS air masses. LS data were analysed using equivalent latitudes. In the UT, pronounced increases of 20–40% are found over the Middle East and South Asia in the spring and summer seasons. Increases are also found over Japan, Europe, and the eastern parts of the United States depending on season. LS ozone over northern mid- and high latitudes was found to be lower in the 1990s compared to the 1970s in all seasons of the year. In addition, a comparison with long-term changes deduced from ozonesondes is presented. The early 1970s European Brewer-Mast (BM) sonde data agree with GASP within the range of uncertainty (UT) or measured slightly less ozone (LS). In contrast, the 1990s BM sensors show consistently and significantly higher UT/LS ozone values than MOZAIC. This unequal behaviour of aircraft/sonde comparisons in the 1970s and 1990s leads to differences in the estimated long-term changes over Europe: while the comparison between GASP and MOZAIC indicates ozone changes of −5% to 10% over Europe, the sondes suggest a much larger increase of 10%–35% depending on station and season, although statistical significance is not conclusive due to data sample limitations. In contrast to the BM sondes, the Electrochemical Cell (ECC) sonde at Wallops Island, USA, measured higher UT ozone than both GASP and MOZAIC. Hence, long-term changes from GASP/MOZAIC agree within the range of uncertainty with the changes deduced from Wallops Island.

Publications Copernicus
Download
Citation
Final-revised paper
Preprint