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Level-2 nadir total ozone column data sets

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Homogenized total ozone data sets have been reprocessed using the retrieval algorithm GODFITv3 from the full time series of the following instruments:

  • The Global Ozone Monitoring Experiment (GOME) aboard ERS-2
  • The SCanning Imaging Absorption SpectroMeter for Atmospheric CartograpHY (SCIAMACHY)  on Envisat
  • GOME-2 on Metop-A and Metop-B
  • OMI on AURA

Time coverage of the reprocessed individual level-2 data sets

GOME/ERS-2 Mar96–Jun11
SCIAMACHY/Envisat Aug02–Mar12
GOME-2/Metop-A Jan07–Dec14
GOME-2/Metop-B Jan 13-Dec14
OMI/Aura Oct04-Dec14


The retrieval algorithm is based on a direct-fitting approach in which sun-normalized radiances simulated with the radiative transfer model LIDORT are adjusted to measurements in the fitting window 325-335 nm. The consistency between the individual data sets has been significantly improved with a soft-calibration scheme of the level-1 data. More details on the algorithm can be found in:

  • Algorithm Theoretical Basis Document (ATBD)
  • Van Roozendael, M., R. Spurr, D. Loyola, C. Lerot, D. Balis, J.-C. Lambert, W. Zimmer, J. van Gent, J. van Geffen, M. Koukouli, J. Granville, A. Doicu, S. Otto, C. Fayt, C. Zehner, Sixteen years of GOME/ERS2 total ozone data: the new direct-fitting GOME Data Processor (GDP) Version 5--Algorithm Description, J. Geophys. Res., vol. 117, No. D3, D03305, 2012.
  • Lerot, C., et al., Homogenized total ozone data records from the European sensors GOME/ERS-2, SCIAMACHY/Envisat and GOME-2/MetOp-A. J. Geophys. Res.,  119, 3, 1639-1662, doi:10.1002/2013JD020831, 2014.


DOWNLOAD the level 2 nadir total ozone data sets. For each sensor are provided:

  • Orbit files: one NetCDF file per orbit
  • Overpass files: One ASCII file per station (overpass radius: 150 km – 322 stations)
  • Gridded data: one ASCII file per day
  • Zonal means: one ASCII file with daily  5°-latitude band means.

More details on the format of the NetCDF files is given in the Product User Guide (PUG)

Contact: Christophe Lerot (christophe.lerot ( at )


Total ozone columns retrieved from GOME-2 on 18th of October 2007


Time series of total ozone zonal mean from March 1996 until December 2012