sentinel-4 and -5 status and level-2 products

Ben Veihelmann, Jörg Langen, Dirk Schüttemeyer, Paul IngmannESA/ESTEC

Sentinel-4 and -5Status and Level-2 Products

OMI Science Team Meeting 18March 2014, KNMI, De Bilt, The Netherlands

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 2

Overview

• Sentinel-4: mission implementation and Level-2 products • Sentinel-5: mission implementation and Level-2 products• AROMAT campaign: preparation of future validation


The Sentinel Missionsfor Copernicus Atmosphere Services

GEOstationary (GEO)– 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 Sentinel-5 Precursor


Sentinel-4/-5/-5P Mission Implementation

Mission InstrumentUtilization 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 infraredFCI = Flexible Combined ImagerIRS = InfraRed SounderLI = Lightning Imager

UVNS = UVN + Short wave infraredVII = 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 GenerationMetOp-SG = MetOp-Second GenerationSNPP = Suomi National Polar-orbiting Partnership JPSS = Joint Polar Satellite System


Sentinel-4/UVN Instrument

External MLI

NIR FPA

NIR Spectrograph

Co-Registration Compensator

UV-VIS Spectrograph

Base Plate

Kinematic Mounts

UV-VIS FEE

Nadir Baffle top Part

Telescope

Calibration Assembly

Scanner

Scanner Cover

TSA Structure

UV-VIS FPA

X

Z

Sun CalibrationView Port

EarthView Port

East-West Scan Range

Cour

tesy

Ast

rium


Sentinel-4/UVN Instrument Characteristics

Radiometric accuracy 1.8% (315-500 nm), 2.3% elsewhere

Polarisation sensitivity <0.7%

Spectral features <0.05%

Signal-to-Noise Ratio compliant

Spatial Sampling 8 km at 45˚N

Geographic Coverage Area (GCA) Europe + Sahara

Repeat Cycle 1 h over Reference Area (RA)400 600 800500 700300

UV-vis NIR

Wavelength (nm)

SpectralBand range

[nm]resolution

[nm]sampling

ratioUV 305 - 400 0.5 3VIS 400 - 500 0.5 3NIR 750 - 775 0.12 3


Sentinel-4 Level-2 Products

ProductApplication

CommentAir Quality Climate Surface

UV

O3 total & tropospheric column X X

O3 enhanced sensitivity to lower troposphere

X X Synergy with infrared data from IRS

NO2 total & trop. column X

SO2 total column X Also for volcanic eruption monitoring

CHOCHO total column X By-productCH2O total column X

Aerosol extinction coeff. profile, column optical depth / type / index X X

Also for volcanic eruption monitoringAlso auxiliary for other S4 productsSynergy with imager data from FCI

Cloud optical thickness, fraction, altitude X Mainly auxiliary for other S4 products

Synergy with imager data from FCI

Surface reflectance daily map X Mainly auxiliary for other S4 products

Who takes care of IRS alone products such as CO, HNO3?


Sentinel-4 Level-2 Performance Estimate(IUP, RAL, Noveltis)

Assumptions • polluted scenario at 50˚N, 15h local time • radiometric offset error small, spectral calibration successful • cloud fraction up to 20%

Tropospheric column O3 [%] NO2 [%] CH2O [%] SO2 [%]

Error type Ran. Sys. Ran. Sys. Ran. Sys. Ran. Sys.Instrument 3 3 7 3 13 3 5 10Scene (clear) 9 20 10 21 7 27 12 20Scene (cloudy) 9 22 11 26 9 34 19 36Total (clear) 22 25 31 25Total (cloudy) 24 29 37 42User req. 10-25 15-25 20-50 20-50


Sentinel-4 Level-2 Performance Estimate(IUP, RAL, Noveltis)

Assumptions: European background aerosol profile

Use

r r

equi

rem

ent

Valuable aerosol data from O2A band in morning/afternoon expected

Aerosol Optical Depth Noise Error

Tota

l Co

lum

nBo

unda

ry

Laye

r

06h 09h 12h 15h 18h

R. S

idda

ns, S

TFC

Ruth

erfo

rd A

pple

ton

Labo

rato

ry


Sentinel-4 Level-2 Processor Development Challenges

Tropospheric NO2 diurnal variation• good precision and accuracy • avoid diurnal biases!• need to account for

– surface anisotropy– tropospheric profile – stratospheric sub-column– aerosol vertical distribution– aerosol phase function

Aerosol & surface characteristics• joint retrieval from aggregated data• little heritage• processor architecture• computational speed

Aerosol layer height• from O2A band• little heritage• spectroscopy• pseudo-noise mitigation• spectral calibration• computational speed


Sentinel-4 Level-2 Pre-development SURMACED (BIRA, GC, LOA, IM)GPGPU (LOA, Catalyst)

Objective• Aerosol & surface reflectance from temporally aggregated radiance• Application to real satellite measurements• Validation based on real measurement

Approach• SURMACED (finalised): GRASP algorithm, performance demonstrated for

favourable illumination conditions (summer), driver NO2 retrieval• GPGPU (ongoing): Proxy data from GOCI, reference from AERONET and

PARASOL

Bi-directional Reflectance Factor, 440 nm, various surface types

GOCI on COMS


Sentinel-4 Level-2 Pre-development AEROPRO (KNMI)

Objectives• Aerosol layer height retrieval from O2A-band• Application to real satellite measurements• Validation based on collocated measurements

Status • GOSAT (0.016 nm) + airborne lidar finalised• GOME-2 (0.5 nm) + ground based lidar almost finalised• poster Bram Sanders

GOME-2 on MetOp

TANSO on GOSAT

CarbonExp Campaign 2011

Lidar on FAAM


CollocatedGOSAT target mode airborne lidar



Sentinel-4 Level-2 Processor Development

• ITT early 2014 • Build on heritage• Challenges• Consortium formation now!


Mission Elements: Sentinel–5LEO Atmospheric Mission

Instrumentation: • UV-VIS-NIR-SWIR spectrometer• Use of thermal IR sounder, cloud

imager and polarisation imager

UV-Visible (270-500nm) NIR (685-775nm) SWIR (1590–1675nm; 2305-2385nm) Spectrometers with spectral resolutions between 0.25 nm and 1.0 nm Spatial sampling with 50 (T)/15 (G) km < 300nm and 15 (T)/5(G) km > 300 nm Global daily coverage Sun-synchronous Low Earth Orbit platform at 824 km mean altitude Embarked on EPS-SG, operated by EUMETSAT

Applications: • air quality, climate forcing and

stratospheric ozone, tropospheric chemistry


Possible Level-2 Products from Sentinel-5 UVNS

species priority

applications

O3 vertical profile 1 SO, AQ, CLO3 total column 1 SONO2 total & trop. col. 1 AQCH4 total column 1 CLCO total column 1 AQ, CLSO2 total column 1 (1) AQHCHO total col. 1 AQBrO total column 2 SOH2O total column 2 AQ, CLCHOCHO total col. 2 AQCO2 total column CL

(1) Only observed in strongly polluted areas (volcanic eruptions, major power plants)(2) Priority 1 not as geophysical product itself, but for use in correcting retrievals of other products(3) Priority 2 for instrument development; priority 1 for Level-2 product development

species priority applications

Cloud optical depth, fraction, height 1 (2)

auxiliary

Aerosol absorption index 2 AQ, CLAerosol optical depth, type

1/2 (3) AQ, CL

Aerosol vertical profile 1/2 (2) AQ, CLSurface reflectance 2 auxiliaryVegetation fluorescence science

SO = stratospheric ozone AQ = air qualityCL = climate


Possible Sentinel-5-relevant Level-2 Products from other instruments on Metop-SG

IAS (IASI-NG)O3 and CO profilesSO2, NH3, CH3OH, HCOOHCH4, H2O, HNO3, PANC2H2, HCNCFC-11, CFC-12, C2H4, N2O, HONO, CO2, volcanic ash

3MIaerosol/cirrus optical depthaerosol single scattering albedo, effective radius, refractive indexsurface reflectance

VII (MetImage)aerosol/cirrus optical depthaerosol type, effective radius, single scattering albedocloud characterisation


Sentinel–5 scientific study activities

Consolidation of requirements• radiometric errors (offset, scaling, spectrally varying)• spatial co-registration (cloud, surface albedo impact), spatial resolution• spectral resolution vs. SNR• knowledge of slit function• added value of O2-B band

Performance assessment• error budget• band trade-offs (eg. 2-band vs. 3-band CH4 retrieval)• vertically resolved aerosol product• spectroscopic errors• fluorescence


AROMAT (Airborne ROmanian Measurements of Aerosols and Trace gases)

Objectives• To combine airborne, satellite and coincident ground activities • To investigate consistency and complementarity of different

measurement approaches

Targets• NO2, SO2, and aerosols in exhaust plumes of large power stations

(Turceni and Rovinari) and around the Bucharest urban area.

Setup• 2 imaging DOAS, scanning lidar, NO2 sondes • high pollution levels and strong gradients

Ben Veihelmann, Jörg Langen, Dirk Schüttemeyer, Paul IngmannESA/ESTEC

Sentinel-4 and -5Status and L2 Products

OMI Science Team Meeting 18March 2014, KNMI, De Bilt, The Netherlands

Thanks for listening!


Backup slides


Preliminary spectral fit-windows per Level-2 product

Surface

Cloud

Aerosol

CHOCHO

HCHO

SO2

NO2

Ozone

300 350 400 450 500 550 600 650 700 750 800Wavelength [nm]

UV-Visible band Near Infrared band


Sentinel-4 Instrument on Meteosat Third Generation (MTG)

MTG-ImagerFlexible Combined Imager (FCI)Lighting Imager (LI)

MTG-SounderInfraRed Sounder (IRS) Sentinel-4/UVN (S4/UVN)

UVN = UV + Visible + Near infrared

http://svr-pluto.esa-ad.esa.int/mtg/Photos%20%20Images/MTG-03_P_CARRIL.jpg

sentinel-4 and -5 status and level-2 products

Documents

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