OSIRIS O3 and NO2 Climatologies from FMI Retrievals

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OSIRIS O3 and NO2 Climatologies from FMI
Retrievals

• Simo Tukiainen,
• Erkki Kyrölä, Seppo Hassinen, Annika Seppälä,
  Johanna Tamminen, Harri Auvinen
• Finnish Meteorological Institute

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Outline

• OSIRIS data processing
• Validation results
• 2003 Climatologies
• Summary

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OS(IRIS) instrument

• UV-visible spectrograph on board the Odin
  satellite
• Spectral range of 280 to 800 nm with 1 nm
  resolution
• Measures limb scattered solar light from 10 to
  100 km

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FMI retrievals

• Data processing of OSIRIS L1 to L2
• Onion peeling type inversion method
• Target species ozone, NO2, ( aerosols, neutral
  air)
• Used wavelengths around 300 pixels for ozone,
  430 450 nm band for NO2
• Reference spectrum first measurement below 50 km
  from each scan

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Ozone Validation

• Comparison with the GOMOS night time occultations
• Coincidence criteria latitude lt 2?, longitude
  lt 10?, time lt 1 day
• ? 546 matches

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OSIRIS GOMOS comparison, January - June 2003
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Differences as a function of latitude
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MOP vs. Flittner-Chappuis 2.5
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NO2 Validation

• Comparison with the HALOE sunset measurements
• Neutral air from the FMI OSIRIS retrievals
• Coincidence criteria latitude lt 3?, longitude
  lt 15?, time lt 1 hour
• ? 38 matches

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OSIRIS HALOE comparison, January - June 2003
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Neutral Air product vs. ECMWF
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Summary

• Reprocessing of the new L2 data is on its way
• Difference between GOMOS and OSIRIS ozone usually
  less than 5
• OSIRIS measures less ozone than GOMOS below 20 km
• NO2 consistent with the HALOE data from 20 to 40
  km
• GOMOS OSIRIS is an useful combination for
  studying e.g. diurnal variations

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Thank You! Questions?