In the framework of AC SAF (formerly O3M SAF), BIRA-IASB coordinates the validation and Quality Assessment (QA) activities for GOME-2 and IASI minor trace gases on METOP plaforms.

This website gathers the latest results of validation and QA for Metop-A and Metop-B minor trace gases, such as NO2, BrO, HCHO, SO2, glyoxal, CO, HNO3 and OClO.
The Validation tab groups the studies made for the new products before reaching operational status (e.g., development of new gases and application of the products to Metop-B), while the Quality Assessment (QA) tab (here) presents the regular online monitoring of the operational products.

Direct link to the QA results.


Latest news


IASI HNO3 validation 18 May 2022 - Validation of IASI-C HNO3 product. Consult the validation report here
GOME-2 tropospheric BrO data record 2 May 2022 - Tropopsheric BrO column data record released. Consult the validation report here
GOME-2 Metop-A November 2021 - Deorbiting of MetopA
GOME-2 glyoxal data record 8 June 2021 - Total CHOCHO column data record released. Consult the validation report here
IASI SO2 validation April 2021 - Validation of IASI-C SO2 product. Consult the validation report here
GOME-2 Metop-C SO2

15 April 2021 - GOME-2C SO2 total columns are declared operational (instead of demonstrational stutus). Consult the validation report here

GOME-2 Metop-C March 2021 - inclusion of GOME-2 MetopC validation results in the Validation Results page and switch to MetopB and MetopC quality assessmnent monitoring instead of MetopA and B.
GOME-2 Metop-A solar gap 30/07/2020 - GOME-2 Metop-A level-1B processing is switched to the empirical solar model, due to the entering in the 4th and last period of solar visibility loss, until the end of mission of Metop-A.
GOME-2 Metop-C NO2, HCHO, BrO validation May 2020 - Validation of NO2, HCHO and BrO GOME-2 MetopC data products (new validation reports)
GOME-2 Metop-A 3rd solar gap 3rd period of GOME-2 Metop-A no solar visibility from the 14th of November 2019  to the 16th of April 2020
GOME-2 Metop-A 2nd solar gap 2nd period of GOME-2 Metop-A no solar visibility from the 26th of December 2018, 11:44 UTC to the 21 of March 2019, 10:28:37 UTC.
GOME-2 MetopC 14 January 2019 - GOME-2 FM1 Metop-C In-orbit Verification (GIOV) campaign is finished, start of the commissioning phase.
GOME-2 MetopC solar spectrum 02/01/2019 - first GOME-2 FM1 Metop-C solar spetrum measured on the 19th October 2018 11:16 UTC
IASI CO validation since Dec. 2018, IASI Metop-A and Metop-B validation is included in the AC SAF regular Operation Reports


October 2018: succesful launch of Metop-C
GOME-2 Metop-A 1rst solar gap

Loss of GOME-2/Metop-A solar calibration between 26/01/2018-19/02/2018:

The Metop-A satellite with GOME-2 on-board is currently in drifting orbit. As a consequence there will be periods in the future during which the GOME-2 instrument will not be able to carry out its daily solar calibration measurement.

The first such period will be from 26th January 2018 to 19th February 2018 (24 days). During this period, the solar mean reference spectrum provided in the Metop-A/GOME-2 level-1B product will be automatically replaced by a modelled solar spectrum using information on solar activity from Metop-B. Therefore, it is expected that the product quality of both level-1B and level-2 products might undergo slight changes during this period. Thus, there will be a risk of degraded product quality for GOME-2 Metop-A products during these days.

IASI SO2 May 2017 - Validation of IASI SO2 MetopA and MetopB data products
GOME-2 OClO May 2017 - Validation of OClO GOME-2 MetopA and MetopB data records
ACSAF logo  01/03/2017 - The 3rd phase of the CDOP project has started, and the Atmospheric Composition and Monitoring SAF has changed acronym from O3M SAF to AC SAF. See main website


 08/12/2016 -The EUMETSAT Council agreed that the ageing, but still healthy, Metop-A satellite will be exploited on a “drifting” orbit from June 2017 onwards, in order to extend its useful lifetime from 2019 to 2022.
See the press release here.



Since 15th July 2013: Metop-B/GOME-2 products are available and the measurement configuration of Metop-A/GOME-2 has been changed to the narrow swath mode (960km). Metop-B/GOME-2 instrument is measuring with in the default mode of 1920 km swath since that day.

More information on tandem operations (EUMETSAT site)

More information on O3M SAF L2 Metop-B products