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

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 3

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

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 4

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

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 5

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

Cou

rtesy A

str

ium

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 6

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)

Spectral

Band range [nm]

resolution [nm]

sampling ratio

UV 305 - 400 0.5 3

VIS 400 - 500 0.5 3

NIR 750 - 775 0.12 3

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 7

Sentinel-4 Level-2 Products

ProductApplication

CommentAir Quality

ClimateSurface

UV

O3 total & tropospheric column X X

O3 enhanced sensitivity to lower

troposphereX 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-product

CH2O total column X

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

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

Cloud optical thickness, fraction, altitude

XMainly auxiliary for other S4 productsSynergy 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?

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 8

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 10

Scene (clear) 9 20 10 21 7 27 12 20

Scene (cloudy) 9 22 11 26 9 34 19 36

Total (clear) 22 25 31 25

Total (cloudy) 24 29 37 42

User req. 10-25 15-25 20-50 20-50

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 9

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

Assumptions: European background aerosol profile

User

req

uir

em

en

t

Valuable aerosol data from O2A band in morning/afternoon expected

Aerosol Optical Depth Noise Error

Tota

l C

olu

mn

Bou

nd

ary

Layer

06h 09h 12h 15h 18h

R. S

idd

an

s, S

TFC

Ru

therf

ord

Ap

ple

ton

Lab

ora

tory

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 10

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 functionAerosol & 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

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 11

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

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 12

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

CarbonExp Campaign 2011

CollocatedGOSAT target mode airborne lidar

CarbonExp Campaign 2011

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 13

Sentinel-4 Level-2 Processor Development

• ITT early 2014

• Build on heritage

• Challenges

• Consortium formation now!

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 14

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

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 15

Possible Level-2 Products from Sentinel-5 UVNS

species priority

applications

O3 vertical profile 1 SO, AQ, CL

O3 total column 1 SO

NO2 total & trop. col. 1 AQ

CH4 total column 1 CL

CO total column 1 AQ, CL

SO2 total column 1 (1) AQ

HCHO total col. 1 AQ

BrO total column 2 SO

H2O total column 2 AQ, CL

CHOCHO total col. 2 AQ

CO2 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, CL

Aerosol optical depth, type

1/2 (3) AQ, CL

Aerosol vertical profile 1/2 (2) AQ, CL

Surface reflectance 2 auxiliary

Vegetation fluorescence   science

SO = stratospheric ozone AQ = air qualityCL = climate

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 16

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

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 17

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

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

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!

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 20

Backup sl

ides

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 21

Preliminary spectral fit-windows per Level-2 product

Surface

Cloud

Aerosol

CHOCHO

HCHO

SO2

NO2

Ozone

300 350 400 450 500 550 600 650 700 750 800

Wavelength [nm]

UV-Visible band Near Infrared band

OMI STM 18 | KNMI De Bilt, NL | March 2014 | Slide 22

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