Near real-time high-resolution ozone profile

Images of the most recent Metop-B near real-time high-resolution ozone profile (from TEMIS website)


Near real-time (NRT) high-resolution vertical ozone profile product provides an ozone profile from the GOME-2 nadir scanning mode, the full error covariance matrix, the retrieval noise covariance matrix, the a-priori profile, the averaging kernels and the retrieved auxiliary parameters, like surface or cloud albedo. Also included are: geo-location, the specific spectral windows used and retrieval diagnostics, like the number of iterations and spectral fit indicators.


Near real-time. Based on product requirements, the product files must be available to users in less than three hours from sensing.


High resolution

  • Metop-A: 40 x 80 km2 (2010 – 16/07/2013) and 40 x 40 km2 (16/07/2013 – present).
  • Metop-B: 40 x 80 km2 (12/12/2012 – present).

Theoretical basis

Global Ozone Monitoring Experiment-2 (GOME-2) measures the radiance spectrum of sunlight scattered from the atmosphere in the (UV) wavelength region 260-330 nm. The absorption of ozone decreases with increasing wavelength. This differential absorption makes it possible to derive the vertical distribution of ozone in the atmosphere from the measured UV spectrum.

Processing algorithm

At KNMI, Ozone ProfilE Retrieval Algorithm (OPERA) iteratively finds the vertical ozone profile best matching the GOME-2 reflectance using optimal estimation. The forward model is based on LidortA and uses an externally prescribed instrument response slit function. The a priori ozone climatology is (currently) based on McPeters/Labow/Logan. The surface pressure and the vertical temperature profile come from operational ECMWF forecasts. Special adaptations have been made to handle spikes in the measured radiance spectrum in the South Atlantic Anomaly.

Units and spatial resolution

The vertical ozone profiles are given as partial ozone columns in Dobson Units (DU) in 40 layers from the surface up to 0.001 hPa. The ground pixel size corresponds to the footprint of the Band-1b integration time, which usually means 40 x 80 km2 (along-track x cross-track, see also resolution above).


This product is validated by DWD (Germany) and KMI (Belgium). The validations are based on detailed comparisons of the operational retrieved profiles from GOME-2 satellite data with ground-based measurements (balloon soundings, lidar and microwave radiometer measurements). Visit AC SAF ozone profiles validation website for further information.


See NRT access information.

File format

The ”shortened” product with reduced information content for easy use in Meteorological Forecasting Models.
Each NRT ozone profile product file contains one PDU (Product Dissemination Unit), which is equal to three minutes of satellite data.

Algorithm version information

Time period GOME-2 / Metop-A GOME-2 / Metop-B
until 29.04.2010 1.01 N.A.
29.04.2010 – 13.05.2013 1.10 N.A.
13.05.2013 – 15.07.2013 1.11 N.A.
15.07.2013 – 23.02.2015 1.11 1.11
23.02.2015 - 13.08.2018 1.12 1.12
13.08.2018 - 19.11.2018 1.30 1.30
19.11.2018 onwards 2.00 2.00

Important changes in the latest algorithm version (2.00)

  • Degradation correction