Sentinel-4 and Sentinel-5 Overview and Status Ben Veihelmann, Jörg Langen ESA/ESTEC

Copernicus Atmosphere Monitoring Service Operational information services for policy makers, …, citizens Protocol compliance monitoring: ozone layer (Montreal, …), air quality (Göteborg, …), climate (Kyoto, …), emission verification Near-real-time services: Local air quality, health warning, aviation routing Assessments: Improve understanding of processes, validate chemical transport models, ground measurement networks Pre-operational: MACC, http://atmosphere.copernicus.eu Uses observations from current satellites, in the future also from Sentinel-4, -5, -5P, … 2

The Copernicus Atmospheric Missions: Sentinel-4, -5p and -5 Environmental Themes stratospheric ozone and surface UV air quality climate Missions and Services Sentinel-4 Sentinel-5p Sentinel-5 regional AQ at 1h temporal res. emission and abundance monitoring forecast global AQ at 1d temporal res. emission and abundance monitoring forecast climate GHG emission monitoring aerosol ozone long term O3 evolution (total column and low resolution profile) surface UV (health) first AQ mission approved for geostationary orbit (embarked on MTG-S) diurnal variation, e.g. NO2, aerosol part of CEOS virtual constellation bridging between OMI and S-5 CO and CH4 x6 step in 2-D spatial resolution vs. OMI some diurnal information (with GOME-2) continuity and long-term datasets synergies with meteo payloads (embarked on Metop-SG) CH4 from 2 bands Some CO2 (quality not sufficient for operational monitoring) boundary conditions for S-4

Requirements Flow GMES implementation group (2009) High-level user needs Capacity study (2005) User requirements Camelot study (2009) Mission requirements S-4/-5 MAG System requirements Instrument development L2 product requirements Level-2 product development

GEO+LEO GEOstationary (GEO) Low Earth Orbit (LEO) Hourly revisit time over Europe Mainly air quality Diurnal cycle of tropospheric composition Sentinel-4 Low Earth Orbit (LEO) Daily revisit time global coverage Climate, air quality, ozone & UV Tropospheric & stratospheric composition Sentinel-5 (9h30 orbit) Sentinel-5 Precursor (13h30 orbit)

Utilization of data from GEO+LEO Mission Instrument Utilization of data from Imager Infrared sounder Other Sentinel-4 UVN spectrometer (1) FCI (2) IRS (1) LI (2,*) Sentinel-5 UVNS spectrometer (3) VII (3) IAS (3) 3MI (3) Sentinel-5 Precursor UVNS spectrometer TROPOMI (4) VIIRS (5) CRIS (5,*) OMPS (5,*) (1) on MTG sounder (GEO) (2) on MTG imager (GEO) (3) on MetOp-SG (LEO) (4) on dedicated platform (LEO) (5) on SNPP/JPSS (LEO) (*) synergy on higher data level UVN = Ultraviolet + Visible + Near infrared FCI = Flexible Combined Imager IRS = InfraRed Sounder LI = Lightning Imager UVNS = UVN + Short wave infrared VII = Visible/Infrared Imager (MetImage) IAS = Infrared Atmospheric Sounder (IASI-NG) 3MI = Multi-viewing, -channel, -polarisation Imager TROPOMI = TROPOspheric Monitoring Instrument VIIRS = Visible Infrared Imaging Radiometer Suite CrIS = Cross-track Infrared Sounder OMPS = Ozone Mapping Profiler Suite MTG = Meteosat Third Generation MetOp-SG = MetOp-Second Generation SNPP = Suomi National Polar-orbiting Partnership JPSS = Joint Polar Satellite System

KARI GEMS JAXA GMAP-ASIA GEO+GEO+GEO+LEO NASA TEMPO ESA Sentinel-4 KARI GEMS JAXA GMAP-ASIA CEOS Atmospheric Composition Virtual Constellation www.ceos.org/images/ACC/AC_Geo_Position_Paper_v4.pdf USA TEMPO Europe Sentinel-4 Korea GEMS Sentinel-5/-5P Orbit Geostationary LEO Domain North America Europe and surrounding Asia-Pacific global Revisit [h] 1 hour Daily, more @ higher lat Spectral ranges UV-Vis UV-Vis-NIR UV-Vis-NIR-SWIR Key products O3, NO2, SO2, HCHO, CHOCHO, aerosol O3, NO2, SO2, HCHO, CHOCHO (TBC), aerosol O3, NO2, SO2, HCHO, aerosol O3, NO2, SO2, HCHO, CHOCHO, aerosol, CH4, CO, … Spatial resolution [km2] 9 x 5 at 35°N 8 x 8 at 40°N 8 x 7 (gas), 8 x 3.5 (aerosol) at 38°N 7 x 7 at nadir

Sentinel-4 UVN Instrument Optical Instrument Module Optical Path Sun calibration Sun Baffle Diffuser Wheel Diffuser Wheel Drive White Light Source Scan Mirror Aperture Cover NIR FPA Beam Splitter Assembly NIR Spectrometer OA TSA Structure Grating GRISM Assembly UV-VIS Collimator UV-VIS Camera UV-VIS FPA Telescope Summer FoV Heater Envelope Scanner Cover YUVN ZUVN XUVN Thermal Heat Shields

Sentinel-4/UVN Instrument Revisit time 1h Geographic coverage Europe + part of Atlantic + part of Sahara, FoV = 4° N/S, 11°-14° E/W Spatial sampling 8 km at 45°N, 530 x 570 spatial samples Spatial resolution 8.9 km N/S, 11.7 km E/W at 45°N Spectral range UV-VIS: 305-500 nm, NIR: 750-775 nm Spectral resolution UV-VIS ≤ 0.5 nm, NIR ≤ 0.12 nm Spectral sampling ratio >3 Envelope 1000 x 1000 x 1500 mm3 Mass 200 kg Power 180 W Data rate (nominal operation) 30 Mbps

Sentinel-4/UVN Scan Strategy Instantaneous Field of View SZA = 90 ° SZA = 92° equinox

Sentinel-5 UVNS Instrument

Sentinel-5/UVNS Instrument Temporal resolution ≤ 24 h Geographic coverage global Spatial sampling < 45 km (270-300nm), < 7.5 km (> 300nm) at nadir; 216 samples within 2670 km swath Spatial resolution ~ spatial sampling distance Spectral range UV-VIS: 270 – 500 nm, NIR: 685 – 710 nm and 755 – 773 nm, SWIR: 1590 – 1675 nm and 2305 – 2385 nm Spectral resolution 1.0 nm ( UV < 300nm), 0.5 nm (UV-VIS 300 – 500 nm), 0.4 nm (NIR), 0.25 nm (SWIR) Spectral sampling ratio 3 (UV-VIS and NIR), 2.5 (SWIR) Envelope 1145 x 1032 x 1026 mm3 Mass 270 kg Power 300 W Data rate (nominal operation) 20 Mbps

Spatial Footprint GOME-2 Sciamachy OMI Image: Google maps GOME-2 Sciamachy OMI Sentinel-4/-5/5P spatial resolution & sampling Better than heritage (Sciamachy/GOME-2/OMI) Big step toward resolving sources

S-5p expected performance Level-2 Products species Characteristics S-5p expected performance S-4 target performance S-5 priority O3 vertical profile 10-30 % (strat. 6 km res.) enhanced sensitivity to lower trop. (1,4) 1 total column 3.5 – 5 % 3 - 4% trop. column 25 - 40% NO2 total column and trop. column strat. < 10%, trop. 25-50 % 1.5*1015 molec/cm² or 30% (goal) / 50% (threshold) SO2 total column and height 30 – 50 % 1.0*1016 molec/cm² or 80% (goal) / 100% (threshold) HCHO 40 – 80 % 1.5*1016 molec/cm² or 50% (goal) / 100% (threshold) CHOCHO x (4) 50% (goal) / 100% (threshold) (4) CH4 1.5 % - CO < 15 % Cloud optical depth, fraction, height <20 % (all parameters) x (2), x (3,4) Aerosol UV absorption index ~1 AAI 0.3 (goal) / 0.5 (threshold) layer height < 100 hPa 1 km optical depth (OD) 0.05 (SUR) 2 absorption OD fine mode OD x Surface effective reflectance first BRF parameter 0.01 Surface UV spectral irradiance, UV index x (FMI) H2O CO2 BrO OClO IO 3 HDO Synergy with IRS Will exploit FCI L2 cloud product if available Synergetic with FCI L1c funding not yet secured S4 target performance given for VZA and SZA<60° (all products) Cloud fraction <20% (trace gas col) Clear sky (aer, surf, o3 pro)

Sentinel-4 Mission Implementation Status S4/UVN instrument & Level-1b Prototype Processor developed by ESA with Airbus Defence & Space as prime Preliminary Design Review completed Critical Design Review mid 2016 Flight Acceptance Review early 2021 Level-1b geometric processing developed on platform level Level-2 Operational Processor developed by ESA with DLR as prime Kick-off 2 June 2015 Prototype and Operational Processor System Integration & Verification, support to Commissioning EUMETSAT will operate the instrument and process the mission data up to Level-2

Sentinel-5 Mission Implementation Status S5/UVNS instrument & Level-1b Prototype Processor developed by ESA with Airbus Defence & Space as prime System Preliminary Design Review completed Critical Design Review Nov. 2017 Flight Acceptance Review Dec. 2020 Level-2 Prototype Processor will be developed by ESA, Operational Processor by EUMETSAT EUMETSAT will operate the instrument and process the mission data up to Level-2

Schedule + Long-Term Perspective GOME-2 (9.30h) and OMI/TROPOMI (13.30h) provide partial diurnal information, before geostationary missions takes over with hourly data S4 and S5, together with IR sounders and 3MI, will be Europe’s long-term contribution to operational nadir-viewing atmospheric composition sounding The geostationary missions GEMS, S4, and Tempo together with S5/S5P form a global atmospheric composition constellation Guaranteed provision of long-term datasets in synergy with meteorological payloads is based on identical instruments  no innovation on space instrument until 2035/40 Update of geophysical requirements for future successors is under EU responsibility: GMES-PURE contract (2013/14) Requirements Framework for the next generation of the Copernicus Space Component (2015–18) (“small scale exercise” for atmosphere complementing PURE)

Thanks for listening! MetOp-SG B SCA MWI RO ICI Argos–4 MTG-S IRS Sentinel-4 Sentinel-5P TROPOMI MTG-I FCI LI MetOp-SG A METimage IASI-NG MWS RO Sentinel-5 3MI Thanks for listening! Ben Veihelmann, Jörg Langen ESA/ESTEC OMI STM 19, de Bilt, NL, Sept 2015 Graphics: ESA