1. Activities in the framework of GSICS CNES Agency Report
GSICS Annual Meeting
20-24th March 2017, Madison, Wisconsin
Activities in the framework of GSICS
CNES Agency Report
Denis Jouglet & Bertrand Fougnie
for CNES Calibration Center
(CNES-DSO/SI/MO + support from CNES-DNO/OT/PE)

2. Summary CNES Instrument updates CNES Activity summary and actions
S3, S2, IASI A&B&C, IASI-NG, 3MI, Microcarb
CNES Activity summary and actions
The Sentinel framework
Continuation of Sentinel-2 : routine S2A + commissioning S2B
Commissioning of Sentinel-3A optical sensors (OLCI & SLSTR)
The IASI family
Status for IASI-A & B, Preparation of IASI-C
IASI inter-comparison
The V2 of the calibration system SADE/MUSCLE
News from the Lunar activity
Status on actions
Support to GRWG activities
Agency’s personnel supporting GSICS
CNES’s interest on GSICS topics

3. CNES’s Instrument of Interest - Update
CNES instruments or instruments with CNES involvement
Sentinel Missions
S3A/OLCI & SLSTR : routine for S3A (end of ramp-up phase)
S3B/OLCI & SLSTR : launch scheduled end of Nov’17 (satellite tests starting)
S2A/MSI : operational routine – monitoring of the calibrations and performances
S2B/MSI : launched 7th March’17 – the commissioning is just starting
EPS
IASI-A : Operational since 2007 (10y in orbit), consistent with IASI-B < 0.01K, reprocessing on L1data on-going, EOL technology tests in , decom
IASI-B : Operational since 2013, nominal performance (prime)
IASI-C : launch in Oct’18. MetOp-C PLM thermal vacuum tests on-going
EPS-SG : EUMETSAT Polar System Second Generation – launch in 2021
3MI : CNES/EUMETSAT collaboration on level-1 and cal/val activities
IASI-NG : under development (twice better spectral resolution and radiometric noise)
Other sounders
Microcarb : CO2, spectrometer in NIR/SWIR, mission recently decided

4. CNES’s Activities in the framework of GSICS

5. Sentinel-2 Sentinel 2 : MSI Sentinel-2
ESA mission - Operational needs of the European Copernicus Program
Land surface
S2A : Launched in June 2015
S2B : Launched the 7th March 2017
MSI imager : 13 bands from 440 to 2200nm, 10/20/60m, 290km
CNES responsible for the image quality activities during commissioning and support the routine phase :
Include Geometry and Radiometry
MSI
Sentinel-2

6. Sentinel-2 Sentinel 2A Trending over desert Multi-method
Radiometric calibration – some samples…
MODIS wrt S2/MSI
S2/MSI wrt MERIS
Trending over desert
Multi-method

7. Sentinel-3 Sentinel 3 Sentinel-3A OLCI SLSTR
ESA mission - Operational needs of the European Copernicus Program
Oceanography and land monitoring
S3A : launched in February 2016
S3B : to be launched in November 2017
Altimetry + 2 optical sensors OLCI and SLST (follow-on MERIS and AATSR)
OLCI = 21 bands from 410 to 1020nm, 300m, 1270km
SLSTR = 11 bands from 550 to nm, 500m/1km, 1400km
On-board diffusers + Black body (nominal) + Vicarious calibration methods
Sentinel-3A
OLCI
SLSTR

8. Sentinel-3
The nominal calibration is currently derived by ESA using on-board devices
OLCI : two diffusers
+ Spectral calibration (pink panel + fraunhofer)
SLSTR : VISAL (diffuser) + black bodies
CNES will validate radiometry during commissioning
All managed through SADE/Muscle
Rayleigh scattering (absolute) : OLCI and SLSTR
Sunglint (interband) : OLCI and SLSTR
Deep Convective Clouds (interband, monitoring) : OLCI
PICS - desert an snowy sites (monitoring, cross-calibration) :
Bridge to MERIS and AATSR (ENVISAT)
Bridge to MODIS reference
Bridge between Sentinel missions with MSI
Sentinel-3 = A new major experience for methods and combination

9. Sentinel-3 - Commissioning
Main results :
Validation of the ageing observed by diffuser in the early weeks (OLCI)
Validation of the long-term stability
Excellent spectral consistency (OLCI)
Small residual bias in VISNIR for OLCI & SLSTR
Very large bias in SWIR for SLSTR 1 2
Best estimate
S3A
OLCI
OLCI+SLSTR 3
OLCI
OLCI 9

10. Direct IASI-A / B inter-comparison: 2016 update
Statistics on “quasi-SNOs” (50min delay)
Focus on homogeneous and stable scenes, night, as many “A before B” as “A after B”
2016
Results:
Biases between 0 and ~0.1K
Highest bias for short wvn
 Very good cross calibration
 Same behaviour as the previous years, no degradation
2015

11. IASI / CrIS & AIRS inter-comparison: 2016 update
Statistics on SNOs (regional averaging, pseudo-channels)
Results:
Biases between 0 and 0.15K
Highest bias for short wvn
 Same behaviour as the previous years, non degradation
IASI-A - CrIS 2016 (1 year)
IASI-A - AIRS 2016 (1 year)
IASI-B - CrIS 2016 (1 year)
IASI-B - AIRS 2016 (1 year)

12. IASI FM2 on MetOp-A IASI End of Life technology possible tests (TBC):
5 tests on the instrument (redundancies, software patches, etc)
Local improvement of spatial sampling
and possibly spatial resolution: reduction
of swath and increase of spatial sampling
Limb measurements: exploit a Pitch Over manoeuvre of the spacecraft to acquire measurements in the Limb direction.
IASI-A & B inter-calibration : acquire SNO (but limited to ~10 SNO for the moment over the poles. Change of altitude keeping the same local hour is not possible).
Lunar acquisition: acquire the moon in most possible moon phases for calibration purposes

13. V2 of the CNES Calibration System
Many calibration methods & data in SADE/MUSCLE
PICS : 20 desert sites + 4 snowy sites
Oceanic sites : Rayleigh scattering and sunglint
DCC : clouds
Celestial : moon and stars
SADE/Muscle development started in ~2000
Progressive developed through successive upgrades
Limitation of the current – SADE Database
Very large number of data
Architecture to be revised for new application : celestial targets, polarization
Need to improve the Muscle calibration toolbox
Some environments become obsolete
Opportunity to upgrade some tools (including redesign)
Decision to develop a new system in
Specification written in
Development in : KO in October’16, on-going

14. CNES Activity on Lunar Calibration
On-going activity to propose a corrected model
Correction of the residual sensitivity to moon phase : 9th order polynomial mean correction
Spectral and Absolute correction – stars irradiance transferred to moon using PHR-1A
Model derived using Pleiades measurements – Under consolidation and validation
Significant reduction of the dispersion, and residual bias down to 2-3%
Current validity for Pleiades bands – to be tested for a wider spectral range
then potentially move toward an operational form

15. CNES Activity on Lunar Calibration
R&T study on the use of the moon for IASI intercalibration will start this year :
bibliography : Moon in the TIR domain + Inventory of Moon IR properties + example of acquisitions by space infrared sensors.
Analysis of Moon acquisitions by IASI-A & B during CALVAL (partial data over 6 small spectral regions) to test its potential for inter-calibration.
Depending on results, routine acquisitions would be considered
for both IASI A&B
2 phases (~80% &~20%) of the Moon accessible in a cold space view of IASI
(directed towards zenith)
Same Moon phase seen by both IASI in the same hour
 Moon radiometry should be very similar between IASI-A & B
Possibility to make long term monitoring of radiometric calibration
Requires to handle the non uniformity of the Moon and
its size / position in the FOV.
Low amount of data => more noise
Moon seen by IIS (IASI integrated imager)

16. Actions & Recommendations
GRWG h.1 - Lunar surface target selections & auto-mapping
“investigate the possibility for CNES to provide NOAA with Pleiades Moon data in order to support the characterization of uniform target sites
Resp. : approval for a distribution of Pleiades data under license agreement. Request to be addressed to CNES.
GRWG p.3 - Hyperspectral IR comparisons - including TANSO-FTS/2
“EUM + CNES to work on the inter-comparison between CrIS and TANSO-FTS”
IASI/GOSAT-2 : for the moment, no real needs for CNES
GRWG – IASI inter-comparison uncertainty budget as part of the GSICS Reference Traceability and uncertainty report
 on-going, currently on stand-by, but will be ready for end ‘17. Presented next year
Recommendation (GRWG-16)
4g - Way forward on lunar inter-calibration
“CNES and EUM to resolve any differences in formulation of presented lunar inter-calibration approaches.”
 CNES was not able to work on this specific topics.

17. CNES’s Personnel Supporting GSICS
CNES involved in GSICS Research Working Group
Personnel :
Denis Jouglet : Infrared domain and cross-calibration
Bertrand Fougnie : reflective domain and calibration
The CNES Calibration team is involved in various projects (CNES or collaborative projects) providing results and feedbacks to be shared with GRWG.
Members could be in
the expertise team (~10 persons)
the operation team, routine or not (~5 persons)
CNES resources for GSICS GRWG activities are (very) limited.
The activity is mainly :
Sharing of results, analysis, feedbacks
Participation to discussions (specific tasks, WG) during Annual Meeting, Webmeeting and WS
Some analysis could be conducted on very specific tasks

18. CNES’s interest on the GSICS tasks
On the GSICS Agenda items, CNES is especially interested by :
Generally, improvement in all the calibration methods (methodology, performance, error budget)
Improvement on the capability to extract radiometric characterizations from lunar acquisitions : temporal, interband, absolute, cross calibration (but also MTF, straylight…)
Defining a common reference for the solar irradiance
Defining the best radiometric references (to be used at least for cross-calibration)
Identifying relevant hyperspectral data to be used to improve the performance of various methods
Feedbacks on IASI cross-comparisons with other sensors
Document error budgets and traceability of our references
Improve the collection of Users needs and Users feedbacks on GSICS products

19. That’s all Folks !

20. 1 - IASI FM2 on MetOp-A status
Launch in 2006
10th birthday in October 2016
Instrument in good health, very stable
Switch from Nominal to Redundant side in April 2015 (electronic part) has solved alarm reports on the measurement of the mobile cube corner speed.
Compensation device stopped on both IASI in flight in October 2015.
Reprocessing of IASI-A data ( ) on going at EUMETSAT, to make a consistent dataset since launch.
Driven by the L1 format and algorithms changes in 2010 (“Day 2”)
All algorithms and characterization improvements made since launch have been taken into account for L1 reprocessing, leading to a better spectra quality (mostly on spectral quality)
L2 reprocessing will follow

21. 1 - IASI FM2 on MetOp-A status
Strategy for the MetOp-A lifetime extension: to maintain MetOp-A service at least until MetOp-C is operational and IASI data are validated.
BUT the LTAN of MetOp-A and phase with MetOp-B have started to drift already (~30 min/2 years each) => intercalibration biases with IASI-A will be impacted
Start IASI End of Life Experiments after MetOp-C commissioning in 2019 until 2021
MetOp-A passivation in ~2021 maximum.
IASI End of Life technology tests: under instruction by EUMETSAT
17 experiments were proposed
8 were rejected
9 are still under instruction

22. 2 - IASI PFM-R on MetOp-B status
The new correction implementation on board has an impact on climate statistics by breaking the radiometric stability in the time series. Intercalibration with IASI will change.
The IASI data reprocessing with the new correction is impossible, because:
the correction is done in the on-board processing of interferograms
all the interferograms are not transmitted on ground (due to bandwidth constrains)
only the real part of the level 0 spectrum is transmitted on ground, the on-board Fourier transform of the interferogram is thus an irreversible processing
It has been discussed with ISSWG (IASI science working group) and with a larger scientific community during the 4th IASI conference (April 2016).
Some concerns have been expressed, with the L1c radiances themselves, to maintain time series consistency for Climate. The users who need the data in NRT, including NWP, need them as good as possible and hence favor the implementation of the correction. For NWP, the consistency between IASI sounders is very important. It was commented that 0.1K is very unlikely to significantly impact the L2 products.
The discussions with some climatologist led to a consensus : change only IASI-B correction tables to let IASI-A as a stable reference. The situation for IASI-A will be reconsidered after the launch of MetOp-C.

23. 3 - IASI FM3-R on MetOp-C status
FM3 instrument retrofit : change of the 2 mechanisms (scan and cube corner) due to magnet delamination. Instrument optical vacuum in January 2016 at TAS was successful => FM3-R
FM3-R has been delivered to EUMETSAT and integrated on the Metop PLM module in October 2016.
MetOp-C PLM thermal vacuum tests are on-going at ESTEC (March-April 2017)
The launch of MetOp-C is planned in October 2018 from Kourou
MetOp-C will be positioned half orbit apart MetOp-B (has Metop-A was).