Mission Objectives of the Atmospheric Composition Related Sentinels S4, S5 and S5p
Ingmann, Paul; Veihelmann, Ben

Sentinels-4, -5 and -5 precursor (S4, S5, S5p) address the GMES Atmospheric Services (GAS). S4 addresses the geostationary (GEO) component while S5 and S5p fly in a low earth orbit (LEO).

S5p embarks an Ultra-violet Visible Near infrared Short-wave infrared (UVNS) spectrometer. The satellite will be in an early afternoon polar orbit and has the objective to provide information and services on air quality, climate and the ozone layer following launch in 2015. The payload of the mission is the TROPOspheric Monitoring Instrument (TROPOMI) which is jointly developed by The Netherlands and ESA. It will measure key atmospheric constituents including ozone, NO2, SO2, CO, CH4, HCHO and aerosol properties. The TROPOMI concept is based on heritage from both the Ozone Monitoring Instrument (OMI) and the SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY). S5p will continue the existing high spatial resolution data record of OMI, as well as the short-wave infrared measurements of SCIAMACHY. The planned formation flying with the NPP satellite will enable important synergies, including the use of high spatial resolution imager data for enhanced cloud clearing of the observational data. The availability of MetOp, embarking GOME-2 and IASI will provide complementary information on diurnal variabilities.

The S4 baseline instrument is an Ultra-violet Visible Near infrared (UVN) spectrometer which will be embarked on the geostationary Meteosat Third Generation-Sounder (MTG-S) platforms. The instrument shall observe Europe with a revisit time of one hour. 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 observed by the S4 mission are tropospheric densities of NO2, O3, HCHO, SO2, aerosols, and CHOCHO. ESA will develop Level-2 products based on the 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 UVN and the InfraRed Sounder (IRS) on-board the same platform. Synergetic aerosol and cloud products are foreseen based on observations from the UVN and from the Flexible Combined Imager (FCI) on-board the MTG-Imager (MTG-I) platform. Development activities resulting in the operational S4 Level-2 processor are in preparation.

The S5 baseline instrument is an Ultra-violet Visible Near infrared Short-wave infrared (UVNS) spectrometer which will be embarked on one of the two MetOp-Second Generation (SG) platforms. The key parameters observed by the S5 mission are O3, SO2, HCHO, BrO, NO2, CHOCHO, CH4, CO and cloud and aerosol properties. Feasibility studies for the instrument are about to conclude. It is planned to enter implementation phase in the second half of 2013. For S5 scientific activities are centred around requirements consolidation. Foci are at present the optimisation of the Near Infrared (NIR) and of the Short-wave InfraRed (SWIR). In addition, it is planned to investigate the synergy offered by flying together with the infrared sounder (IAS), the multi-viewing/-channel/-polarisation imager (3MI) and MetImage, the baseline imager on-board the same Metop-SG platform.

The presentation at the upcoming symposium will focus on the mission objectives of the three atmospheric composition related Sentinels.