XCO2 retrieval for GOSAT and GOSAT-2 based on the FOCAL algorithm

Autor: Noël, Stefan, Reuter, Maximilian, Buchwitz, Michael, Borchardt, Jakob, Hilker, Michael, Bovensmann, Heinrich, Burrows, John P., Di Noia, Antonio, Suto, Hiroshi, Yoshida, Yukio, Buschmann, Matthias, Deutscher, Nicholas M., Feist, Dietrich G., Griffith, David W. T., Hase, Frank, Kivi, Rigel, Morino, Isamu, Notholt, Justus, Ohyama, Hirofumi, Petri, Christof, Podolske, James R., Pollard, David F., Sha, Mahesh K., Shiomi, Kei, Sussmann, Ralf, Té, Yao, Velazco, Voltaire A., Warneke, Thorsten
Přispěvatelé: Institute of Environmental Physics [Bremen] (IUP), University of Bremen, Earth Observation Science Group [Leicester] (EOS), Space Research Centre [Leicester], University of Leicester-University of Leicester, Japan Aerospace Exploration Agency [Tsukuba] (JAXA), National Institute for Environmental Studies (NIES), University of Wollongong [Australia], Max Planck Institute for Biogeochemistry (MPI-BGC), Max-Planck-Gesellschaft, DLR Institut für Physik der Atmosphäre (IPA), Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR), Karlsruhe Institute of Technology (KIT), Finnish Meteorological Institute (FMI), NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), NASA Ames Research Center (ARC), National Institute of Water and Atmospheric Research [Lauder] (NIWA), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Atmospheric Measurement Techniques
Atmospheric Measurement Techniques, European Geosciences Union, 2021, 14 (5), pp.3837-3869. ⟨10.5194/amt-14-3837-2021⟩
Atmospheric measurement techniques, 14 (5), 3837–3869
ISSN: 1867-8548
1867-1381
DOI: 10.5194/amt-14-3837-2021⟩
Popis: Since 2009, the Greenhouse gases Observing SATellite (GOSAT) performs radiance measurements in the shortwave-infrared (SWIR) spectral region. From February 2019 onward, data from GOSAT-2 are also available. We present first results from the application of the Fast atmOspheric traCe gAs retrieval (FOCAL) algorithm to derive column-averaged dry-air mole fractions of carbon dioxide (XCO2) from GOSAT and GOSAT-2 radiances and their validation. FOCAL has initially been developed for OCO-2 XCO2 retrievals and allows simultaneous retrievals of several gases over both land and ocean. Because FOCAL is accurate and numerically very fast it is currently considered as a candidate algorithm for the forthcoming European anthropogenic CO2 Monitoring (CO2M) mission, to be launched in 2025. We present the adaptation of FOCAL to GOSAT and discuss the changes made and GOSAT specific additions. This includes particularly modifications in pre-processing (e.g. cloud detection) and post-processing (bias correction and filtering). A feature of the new application of FOCAL to GOSAT/GOSAT-2 is the independent use of both S and P polarisation spectra in the retrieval. This is not possible for OCO-2, which measures only one polarisation direction. Additionally, we make use of GOSAT’s wider spectral coverage compared to OCO-2 and derive not only XCO2, water vapour (H2O) and solar induced fluorescence (SIF) but also methane (XCH4), with the potential for further atmospheric constituents and parameters like semiheavy water vapour (HDO) and (in the case of GOSAT-2) also carbon monoxide (CO) total columns and possibly nitrous oxide (XN2O). Here, we concentrate on the new FOCAL XCO2 data products. We describe the generation of the products as well as applied filtering and bias correction procedures. GOSAT-FOCAL XCO2 data have been produced for the time interval 2009 to 2019. Comparisons with other independent GOSAT data sets reveal an agreement of long-term temporal variations within about 1 ppm over one decade; differences in seasonal variations of about 0.5 ppm are observed. Furthermore, we obtain a mean regional bias of the new GOSAT-FOCAL product to the ground based Total Carbon Column Observing Network (TCCON) of 0.56 ppm with a mean scatter of 1.89 ppm. The GOSAT-2-FOCAL XCO2 product is generated in a similar way as the GOSAT-FOCAL product, but with adapted settings. All GOSAT-2 data until end of 2019 have been processed. Because of this limited time interval, the GOSAT-2 results are considered to be preliminary only, but first comparisons show that these data compare well with the GOSAT-FOCAL results.
Databáze: OpenAIRE
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