Retrieval of SO2 columns from FY-3F/OMS instrument observations

Atmospheric SO₂ plays an important role in air quality and climate. Satellite remote sensing enables continuous monitoring of SO₂ from volcanic and anthropogenic sources. The Ozone Monitoring Suite (OMS) onboard the Chinese FY-3F satellite, launched in August 2023, is a new hyperspectral UV–VIS instrument designed for atmospheric trace gas observations. Here we present the global retrieval of SO₂ columns from FY-3F/OMS nadir measurements using a Differential Optical Absorption Spectroscopy (DOAS) approach. Instrument-specific processing schemes, including solar spectrum selection, spectral soft calibration, and background offset correction, were developed to mitigate along-track striping and across-track asymmetry in the initial retrievals. The FY-3F/OMS SO₂ products are evaluated against TROPOMI SO₂ retrievals over clean oceanic regions, volcanic plumes, and anthropogenic emission areas. The results demonstrate good stability over clean regions (precision ~0.15 DU) and a clear capability to detect both volcanic and anthropogenic SO₂ enhancements. Remaining uncertainties are mainly related to detector non-uniformity and AMF. These results provide a first assessment of the FY-3F/OMS capability for global SO₂ monitoring.