The Sentinel-5p TROPOMI L2_SO2 sulphur dioxide column data are found in general good agreement with ground-based MAX-DOAS and PGN measurements and with other satellite observations from OMI and S-NPP OMPS. The bias and dispersion with respect to validation data are typically below 0.2 DU. From these comparisons it can be concluded that over polluted regions the mission requirements are fulfilled. Over volcanic plumes the requirement on the bias is fulfilled, while the dispersion can exceed slightly the requirement on the random component of the uncertainty. . In November 2024 the SO2 processor was changed to the COBRA algorithm (Theys et al., 2021). A reprocessing of the whole dataset has been set up and data was released in summer 2025. The dispersion and biases of the new version are substantially decreased compared to the previous version.
References
Theys, N. et al. A sulfur dioxide Covariance-Based Retrieval Algorithm (COBRA): application to TROPOMI reveals new emission sources, Atmos. Chem. Phys., 2021, 21, 16727-16744, doi.org/10.5194/acp-21-16727-2021doi.org/10.5194/acp-21-16727-2021