The GMES Sentinel-4 Mission Dedicated to Atmospheric Composition
Veihelmann, Ben; Yasjka, Meijer; Ingmann, Paul; Koopman, Rob; Bazalgette, Gregory; Stark, Hendrik

The Sentinel-4 mission, together with Sentinel-5 and the Sentinel-5 Precursor missions, is part of the Global Monitoring for Environment and Security (GMES) space component covering the Earth's atmosphere. The primary objective of the Sentinel-4 mission is the observation of the diurnal cycle of the tropospheric composition in support of the air quality applications of GMES Atmosphere Services. The presentation focuses on the Sentinel-4/UVN instrument and its related Level-2 atmospheric composition products.

The Sentinel-4 instrument is an Ultra-violet Visible Near infrared spectrometer (S4/UVN) which is embarked on the geostationary Meteosat Third Generation-Sounder (MTG-S) platforms. Key features of the S4/UVN instrument are the spectral range from 305 nm to 500 nm with a spectral resolution of 0.5 nm, and from 750 nm to 775 nm with a spectral resolution of 0.12 nm, in combination with a low polarization sensitivity and a high radiometric accuracy. The instrument shall observe Europe with a revisit time of one hour. The spatial sampling distance varies across the geographic coverage area and takes a value of 8 km at a reference location at 45 N. The expected launch date of the first MTG-S platform is 2019, and the expected lifetime is 15 years (two S4/UVN instruments in sequence on two MTG-S platforms).

The key parameters of the Sentinel-4 mission are tropospheric densities of NO2, O3, HCHO, SO2, aerosols, and CHOCHO. ESA will develop Level-2 products based on the S4/UVN measurements for these key parameters and for cloud and surface properties as intermediate products. Synergetic O3 vertical profile product is foreseen based on observations from the S4/UVN and the InfraRed Sounder (IRS) on-board the same platform. Synergetic aerosol and cloud products are foreseen based on observations from the S4/UVN and from the Flexible Combined Imager (FCI) on-board the MTG-Imager (MTG-I) platform. Development activities resulting in the operational Sentinel-4 Level-2 processor are in preparation.