GOME-2 Level 1b processor update:

EUMETSAT plans to update the Level 1b processor to version 7.2.0 for the Metop-B and Metop-C GOME-2 instruments on 8 September 2026.

Since 17 July 2026, GOME-2 on Metop-C has been experiencing increased instabilities in the spectral assignment in channel 2 due to degrading of the onboard Spectral Light Source. The same issue has been affecting the spectral assignment of GOME-2 on Metop-B as well. Consequently, the quality of the solar mean reference spectrum in the GOME-2 L1b product (for channel 2) has been affected for both Metop-B and Metop-C. The degraded L1b product affects the quality of the L2 ozone, SO2 and formaldehyde products provided by the AC SAF.

This spectral calibration issue has been resolved in the updated GOME-2 Level 1b processor (Version 7.2.0) with the implementation of an alternative spectral calibration method using Fraunhofer lines of the solar spectrum.

With the deployment of the updated Level 1b processor, users should expect changes in the L1b products for both Metop-B and Metop-C, especially for the (ir)radiance spectra in channel 2. It is expected that the L2 ozone, SO2 and formaldehyde products will undergo changes as well, but the impact on the other L2 products provided by the AC SAF is expected to be very small. No impact is expected on the centrally generated PMAp products.

The update of the level 1b processor has no effect on the GOME-2 L1b product format.

EUMETSAT will closely monitor the performance of the Level 1b product quality and they would appreciate any feedback from you concerning data quality.

For more details, see: EUMETSAT - User Portal.