Starting from 2019, the Italian Space Agency (ASI) is supporting dedicated projects for the development of new methods, tools and competences for the interpretation and the exploitation of the future measurements of the FORUM (Far-infrared Outgoing Radiation Understanding and Monitoring) experiment.
FORUM will be the ninth Earth Explorer mission of the European Space Agency, scheduled for launch on a polar orbiting satellite in 2027. The core instrument of the mission will be a Fourier Transform Spectrometer with spectral range extending down to the Far-InfraRed (FIR), from 100 to 1600 cm-1 (from 100 to 6.25 microns in wavelength), thus covering the whole Earth's outgoing longwave radiation spectrum.
FORUM will fly in loose formation with the MetOp-SG-A satellite, hosting the Infrared Atmospheric Sounding Interferometer - New Generation (IASI-NG). The Middle-InfraRed (MIR) range (645 to 2760 cm-1) of the upwelling atmospheric spectrum measured by IASI-NG will effectively complement the FORUM measurement. All together, the two missions will provide matching spectral radiance measurements with unprecedented coverage, from 100 to 2760 cm-1.
While the FIR part of the spectrum (100-667 cm-1) measured by FORUM is the most sensitive to the water vapour content in the UTLS and to ice cloud properties, the atmospheric windows in the MIR are measured by IASI-NG with a very high signal-to-noise ratio, thus supplying very precise information on the surface temperature and on the temperature profile, which are essential to constrain the retrieval of the other geophysical parameters.
To get ready for the exploitation of the synergistic FORUM and IASI-NG measurements, in the frame of the mentioned ASI projects a Bayesian retrieval algorithm with the capability to perform the simultaneous inversion of two different synergistic spectral radiance measurements was developed. The tool is named FAst Retrieval Model (FARM) as it is based on a fast monochromatic and parametrized radiative transfer model (?-IASI) which is also being further extended and refined within the same projects. FARM includes the capability to retrieve simultaneously both atmospheric and cloud parameters. Furthermore, the code can handle both air/space- borne nadir measurements and ground- based zenith measurements.
In this work, we introduce the functionalities of the developed algorithm and present the results of the self-consistency and verification tests. The preliminary results of the inversion of some existing real measurements are also discussed.
The FORUM end-to-end simulator project: architecture and results
Sgheri Luca
;
Belotti Claudio
;
BenYami Maya
;
Bianchini Giovanni
;
Dominguez Bernardo Carnicero
;
Cortesi Ugo
;
Cossich William
;
Del Bianco Samuele
;
Di Natale Gianluca
;
Guardabrazo Tomas
;
Lajas Dulce
;
Maestri Tiziano
;
Magurno Davide
;
Oetjen Hilke
;
Raspollini Piera
;
Sgattoni Cristina
FORUM (Far-infrared Outgoing Radiation Understanding and Monitoring) will fly as the ninth ESA's Earth Explorer mission, and an end-to-end simulator (E2ES) has been developed as a support tool for the mission selection process and the subsequent development phases. The current status of the FORUM E2ES project is presented together with the characterization of the capabilities of a full physics retrieval code applied to FORUM data. We show how the instrument characteristics and the observed scene conditions impact on the spectrum measured by the instrument, accounting for the main sources of error related to the entire acquisition process, and the consequences on the retrieval algorithm. Both homogeneous and heterogeneous case studies are simulated in clear and cloudy conditions, validating the E2ES against appropriate well-established correlative codes. The performed tests show that the performance of the retrieval algorithm is compliant with the project requirements both in clear and cloudy conditions. The far-infrared (FIR) part of the FORUM spectrum is shown to be sensitive to surface emissivity, in dry atmospheric conditions, and to cirrus clouds, resulting in improved performance of the retrieval algorithm in these conditions. The retrieval errors increase with increasing the scene heterogeneity, both in terms of surface characteristics and in terms of fractional cloud cover of the scene.
FORUM (Far-infrared Outgoing Radiation Understanding and Monitoring) will flight as the 9th ESA's Earth Explorer mission, and an End-to-End Simulator (E2ES) has been developed as a support tool for the mission selection process and the subsequent development phases. The current status of the FORUM E2ES project is presented, together with the characterization of the capabilities of a full physics retrieval code applied to FORUM data. We show how the instrument characteristics and5the observed scene conditions impact on the spectrum measured by the instrument, accounting for the main sources of error related to the entire acquisition process, and the consequences on the retrieval algorithm. Both homogeneous and heterogeneous case studies are simulated in clear and cloudy conditions, validating the E2ES against two independent codes: KLIMA (clear sky) and SACR (cloudy sky). The performed tests show that the performance of the retrieval algorithm is compliant with the project requirements both in clear and cloudy conditions. The far infrared (FIR) part of the FORUM spectrum is shown to be10sensitive to surface emissivity, in dry atmospheric conditions, and to cirrus clouds, resulting in improved performance of the retrieval algorithm in these conditions. The retrieval errors increase with increasing the scene heterogeneity, both in terms of surface characteristics and in terms of fractional cloud cover of the scene.
2019Rapporto di ricerca / Relazione scientificarestricted access
Earth Explorer 9 Candidate Mission FORUM -- Report for Mission Selection
This report is based on contributions from the FORUM Mission Advisory Group MAGHelen Brindley Imperial College London
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UKStefan A Buehler University of Hamburg
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DEDorothee Coppens EUMETSAT
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INTAdrien Deschamps CNES
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FRSteven Dewitte Royal Meteorological Institute of Belgium
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BEBianca M Dinelli ISACCNR
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ITLaurent Labonnote University of Lille
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FRQuentin Libois MétéoFrance
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FRMartin Mlynczak NASA Langley Research Center
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USLuca Palchetti INOCNR
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ITMarco Ridolfi University of Bologna
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ITMartin Riese Forschungszentrum Jülich
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DERoger Saunders Met Office
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UKThe scientific content of the report was compiled by Hilke Oetjen Scientific Coordinator
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based on inputs derived from the MAG
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supporting scientific studies
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campaignactivities
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with contributions from Richard Bantges
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Marco Barucci
;
Claudio Belotti
;
Giovanni Bianchini
;
Elisa Castelli
;
Simone Ceccherini
;
Bertrand Cluzet
;
Mathieu Compiègne
;
Ugo Cortesi
;
William Cossich
;
Francesco D'Amato
;
Samuele Del Bianco
;
MohamadouAbdoulaye Diallo
;
Gianluca Di Natale
;
Alessio Di Roma
;
Marie Dumont
;
Marco Gai
;
DinaKhordakova
;
Lukas Kluft
;
Tiziano Maestri
;
Davide Magurno
;
Alessio Montori
;
Jonathan EMurray
;
Piera Raspollini
;
Markus Rettinger
;
Christian Rolf
;
Jacqueline E Russell
;
LucaSgheri
;
Ralf Sussmann
;
Silvia Viciani
;
Jérôme Vidot
;
Hannes Vogelmann
;
Laura Warwick
;
the UK FAAM team
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the UK MetOffice
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Dirk SchuettemeyerThe technical content of the report was compiled by Bernardo Carnicero DomínguezTechnical Coordinator
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Charlotte Pachot Payload Technical Coordinator withcontributions from Itziar Barat
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Paolo Bensi
;
Christophe Caspar
;
Miguel Copano
;
MauroFederici
;
Dulce Lajas
;
Flavio Mariani
;
Vasco Pereira
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Stefanie Riel
;
Gonçalo Rodrigues
;
Bernd Sierk
;
Kate Symonds
;
Andrea Tromba
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based on inputs derived from the industrialPhase A system
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technical activities
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the FORUM endtoend performance simulatoractivity under the responsibility of the Future Missions
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Instruments Division Specialthanks go to the industrial teams who have supported ESA to bring this report together in avery short time after the Phase A Preliminary Requirements Review
his report forms the basis for the selection of the ninth Earth Explorer mission within ESA's
Earth Observation Programme. Two competing 'Fast Track' candidates, the Far-infrared
Outgoing Radiation Understanding and Monitoring (FORUM) mission and the Surface
ocean KInematics Multiscale (SKIM) mission. Each have each undergone a rapid and
compressed Phase A feasibility study. This report covers the FORUM mission.
