Sentinel-4 UVN sounder

Sentinel-4 UVN is a passive optical ultraviolet, visible and near-infrared imaging spectrometer hosted on Meteosat Third Generation Sounder satellites for geostationary atmospheric-composition observation. ^{[1] [2]} Its spectral set covers UV 305-400 nm, visible 400-500 nm and near-infrared 755-775 nm, with 600 UV channels, 600 visible channels and 300 near-infrared channels. ^[3] Spatial sampling is about 8 km over the reference area. ^[1] The observing concept provides hourly daytime coverage over Europe and part of North Africa for air-quality trace gases and aerosols, including ozone, nitrogen dioxide and sulphur dioxide. ^{[1] [2]} Sentinel-4 has demonstrated preliminary nitrogen dioxide, sulphur dioxide, ozone and radiance imaging on MTG-S1; those products came from 8 October 2025 scenes and were labelled illustrative rather than operational. ^[4] Those October 2025 scenes support first-data maturity, not routine operational service.