MMP
Monitoring MSI/EarthCARE L1 Performances
using concomitantintercalibration and stand-alone approaches

ARA/ABC(t)/LMD/IPSL
Ecole Polytechnique
Palaiseau
FranceESA UNCLASSIFIED– For ESA Official Use Only

2nd ESA EarthCARE Validation Workshop
25-28 May 2021 (online)1

MMP co-Workers / co-Authors, Supporting Teams/Agencies* Colleagues from LMD: A, Chédin, R, Armante, V. Capelle, L. Crépeau, O, Chomette, M, Capderou* Colleagues from the IIR/Calipso Team and PI: Anne Garnier, Jacques PelonThanks +++ to :* ECMWF to provide access to their radiosonde, analysis and reanalysis data and archive* CNES for opening GSICS doors to a “non operational meteo center”: D. Renaut, P. Henry, D. Jouglet* CNES TEC for fruitful discussions: D. Jouglet, T. Tremas* CNRS and CNES for its more than “n*10 year” supporting of this Work through CNES/TOSCA/IASI andCNES/TOSCA/EECLAT (V. Noël, J. Delanoë et coll.)* AERIS/Icare for the REMAP IIR/Modis/Seviri mapping algorithm : J. Descloitres, J.M. Nicolas, F. Ducos* IDRIS/jean-Zay and AERIS / (ClimServ, Ciclad) computing facilities* AERIS / Ether and AERIS/Icare for Observations Acquisition: IASI, SEVIRI, IIR, etc* AERIS for the distribution of GEISA, 4A/OP, ARSA, TIGR
ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

2MMP : Heritage from a long LEO/GEO processing of vertical sounders @Early 80’s

A technique for the calibration of METEOSAT based on LEO/GEO space and time collocations with instruments onboard the NOAA series(Bériot N., Scott N.A, Chédin A., Sitbon P.J. Appl. Meteor., vol 21, 1982).
From the early 90’s onwards

Similar methods were applied to the processing of AIRS/AQUA, IASI/MetOpA and B, C and IIR/CALIPSO, including
LEO/LEO and GEO/LEO collocations.
- our in-house L2 retrievals NOAA-series, AIRS, IASI, etc- our involvement in the TOVS-NOAA/NASA Pathfinder Programme, then in GSICS activities- Scientific Teams

ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

3A 3-way approach for a Qualitative and Quantitative characterization ofvariations/trends
The relative (aka inter-calibration) approach
The stand alone approach
The double-difference approach : whenever possible
to take advantage of the well assessed radiometricstability of satellites/instruments – e.g. MetOp/IASI

ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

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Why several approaches?
The relative and stand-alone approaches are complementary:- our “inter-calibration” approach compares observed BTs

è “OBS - OBS”

- not restricted to clear scenes è Thousands of instruments collocations- allows wide ranges of brightness temperatures being compared- assesses the behaviour of one channel relative to its companion channel.
- our "stand alone" approach simulates BTs of clear scenes (RT model and surface+atmospheric inputs) andscreens every channel of each instrument, individually. è “SIMUL – OBS”
This complementarity helps:i)identifying which instrument/channel deviates from the other(s) andii) quantifying such trends/variations.
ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

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Lessons learned : Q/C, Q/A activities
Hereafter : Few examples from IASI/MetOp, IIR/Calipso Q/C, Q/A activities
At LMD : This activity is in near-real time on a T-1month basis for IASI, HIRS, AMSU, MHS on MetOp A, B, C
AERIS/Icare : Operational for IIR/Calipso

LMD Model and Databases accessibility
TIGR data set : https://ara.lmd.polytechnique.fr/index.php?page=tigr
ARSA data set : https://ara.lmd.polytechnique.fr/index.php?page=arsa
GEISA spectroscopic database : https://geisa.aeris-data.fr
4A/OP radiative transfer model : https://4aop.aeris-data.fr
Publications : https://ara.lmd.polytechnique.fr/index.php?page=publications
ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

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Qualitative and Quantitative characterization of variations/trends/spurious behaviors… and anything good or wrong which can happen in remote sensing!

ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

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Qualitative and Quantitative characterization of variations/trends/spurious behaviors… and anything good or wrong which can happen in remote sensing!

ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

8A decade (2006-2017) of IIR/CALIPSO L1 assessment against MODIS/Aqua
Complementarity of the Inter Calibration and the Stand-Alone approaches (1/2)
Time series (2006-2017) of IIR-MODIS daily average BTDs
IIR1-MODIS29 (red),
IIR2-MODIS31 (green) andIIR3-MODIS32 (blue).
Latitude range: 30°S-30°N.
Temperature range: 290-300 K. Sea only.

The Inter Calibration results raise aquestion : which channel deviates fromthe other? IIR1 or MODIS 29?

The relative (aka Intercalibration) approach shows aslight trend of the IIR1-MODIS29 BTDs, equal to -0.02
K/year on average, is visible at all latitudes andtemperatures ranges, whereas no trend is seen in theIIR2-MODIS31 and IIR3-MODIS32 BTDs
ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

9A decade (2006-2017) of IIR/CALIPSO L1 assessment against MODIS/Aqua
Complementarity of the Inter Calibration and the Stand-Alone approaches (2/2)
The stand alone approach gives the answer: the MODIS29 residuals (top, red) exhibit a negative
trend of -0.019K/year when the IIR1 residuals are stable

Approach and Results widely described and discussed in Science Groups, Revex, …, and open literature:- Scott N.A. et al GSICS Quarterly Newsletter 2009,- Garnier A., Scott N.A., Pelon J., Armante R., Crépeau L., Six B. and Pascal N. Atmos. Meas. Tech., 10 , 2017.
- Scott N.A. , Garnier A., Pelon J., Armante R. GSICS Quarterly Newsletter, 11, 2017
- Garnier A. , Trémas T. , Pelon J., Lee K., Nobileau D., Gross L., Pascal N., Ferrage P. and Scott N.A. Atmos. Meas. Tech., 11 , 2018.
ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

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A decade (2006-2017) of IIR/CALIPSO L1 assessment against MODIS/Aqua :A contribution to move from version 1 to version 2 of IIR calibration by CNES et coll.
Unexpected, moreover seasonal, IIR-MODIS BTDs day/night differences are seen since launch inthe 30N-60N latitude band, but not south of 30N.
In July, the nighttime BTDs in the descending portion of each orbit are larger than the daytime BTDs by up to 0.2 K to 0.4 K
on average (see example below for year 2008).

IIR Version 1

IIR Version 2 in 2017
after correction by CNES/TEC. Nighttime (blue) and daytime (red) time series of IIR-MODIS daily average BTDs for IIR1-MODIS29 (top), IIR2MODIS31 (middle) and IIR3-MODIS32 (bottom). Latitude range: 30°N-60°N. Temperature range: 280-290 K. Sea only.
ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

11Lessons learned... so far for Q/A and Q/C activities

Pay the highest attention to permanently control all the elements of the observations Q/A , Q/C : models, auxiliary
data sets.
Stay in close contact and interact with PIs and all human actors/teams in charge of the observations or of theprocessing of the observations (L1, L2, …) : feedbacks are of paramount importance….

Reprocessing data (L1,L2, …) is part of the game

ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

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Towards MSI/EarthCARE: The MMP ProjectMMP
Monitoring MSI/EarthCARE L1 Performances
A Close Heritage from the QA/QC of IIR/Calipso through a coupling with Modis/Aqua and Seviri/MSG
for the three 8 to 10 microns channels

ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 202113

Towards MSI : From Pre-Launch Activities to In-Flight real world

Pre-Launch Simulations(IIR-Modis) BTDs
4A/OP + fed with TIGR2000

Real world observed
IIR-MODIS BTDs atwarm temperature
confirm, within 0.3 K, thepre-launch simulations
LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

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MMP STATUS: Pre-Launch Activities (1/2)

Instruments/Satellites candidates
MSI/EarthCare, VIIRS/NOAA-20 , FCI/MTG
Others?

Pre-launch activities ready to startAim :* Select the best companion pairs of channels** Establish interchannel+Interinstrument radiometric stats
For Land/ea/SZA/Air mass types, BTs bins
How:
4A/OP + TIGR è BTs, Jacobians, Transmittances,Sensitivity ç LMD in house models and databases
4A/OP parallel version v1.8 (rel, 2019)
TIGR- 2020 (released 2020)
GEISA-2020 (released 2020)
ARSA v2.8 (to be released 2021)
All available on AERIS and/or LMD Data clusters

ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

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MMP STATUS: Pre-Launch Activities (2/2)

Instruments/Satellites candidates
MSI/EarthCare, VIIRS/NOAA-20 , FCI/MTG
Others? Already in flight?

Pre-launch activities ready to start …..

HOWEVER !.... Some questions for the best possible spatial-spectraltemporal homogeneity

How to get the more reliable ISRF, orbitography, scanning characteristics for
all companion satellites ans instruments?
Spatial homogeneity of the pixels? Spatial averaging required?
Time collocation? Any A-Train like temporal coincidence?
How to minimize the naturally occurring GEO–LEO “mismatch”
Limit the scanning angles to avoid heterogeneous optical pathes?

ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

16

MMP : Technical Approach / Phase 2 = In-Flight activities
Global data will be processed in delayed-mode.
Results will be presented on a day-to-day basis or on a month-to-month basis with distinct day/night,
land/sea outputs, within 10 brightness temperature bins from min-max defined values (e.g. 190 to 330K),
During the lifetime of the instrument, the versions of the radiative transfer model, spectroscopic database,…, used for the pre-launch time characterization will be frozen. If any change had to intervene, the error
evaluation process as well as thresholds values would be revisited accordingly.
Moreover, reference satellites/instruments may undergo variations (spectral, geolocation, etc) during
EarthCARE lifetime: the impact of such changes will be taken into account, evaluated and controlled
owing to the stand alone approach.

ARA/ABC(t)/LMD/IPSL Ecole Polytechnique Palaiseau France

2nd ESA EarthCARE Validation Workshop 25-28 May 2021

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LMD Model and Databases accessibility
https://ara.lmd.polytechnique.fr/
TIGR data set : https://ara.lmd.polytechnique.fr/index.php?page=tigr
ARSA data set : https://ara.lmd.polytechnique.fr/index.php?page=arsa
GEISA spectroscopic database : https://geisa.aeris-data.fr/
4A/OP radiative transfer model : https://4aop.aeris-data.fr/

ARA/ABC(t)/LMD/IPSL
Ecole Polytechnique
Palaiseau
FranceESA UNCLASSIFIED– For ESA Official Use Only

2nd ESA EarthCARE Validation Workshop
25-28 May 2021 (online)
18