ACOS_L2S_7.3

ACOS GOSAT/TANSO-FTS Level 2 Full Physics Standard Product V7.3 (ACOS_L2S) at GES DISC

Version 7.3 eng
  • Abstract
    Version 7.3 is the current version of the data set. Version 3.5 is no longer available and has been superseded by Version 7.3. This data set is currently provided by the OCO (Orbiting Carbon Observatory) Project. In expectation of the OCO-2 launch, the algorithm was developed by the Atmospheric CO2 Observations from Space (ACOS) Task as a preparatory project, using GOSAT TANSO-FTS spectra. After the OCO-2 launch, "ACOS" data are still produced and improved, using approaches applied to the OCO-2 spectra. The "ACOS" data set contains Carbon Dioxide (CO2) column averaged dry air mole fraction for all soundings for which retrieval was attempted. These are the highest-level products made available by the OCO Project, using TANSO-FTS spectral radiances, and algorithm build version 7.3. The GOSAT team at JAXA produces GOSAT TANSO-FTS Level 1B (L1B) data products for internal use and for distribution to collaborative partners, such as ESA and NASA. These calibrated products are augmented by the OCO Project with additional geolocation information and further corrections. Thus produced Level 1B products (with calibrated radiances and geolocation) are the input to the "ACOS" Level 2 production process. Even though the GES DISC is not publicly distributing Level 1B ACOS products, it should be known that changes in this version are affecting both Level 1B and Level 2 data. An important enhancement in Level1B will address the degradation in the number of quality-passed soundings. Elimination of many systematic biases, and better agreement with TCCON (Total Carbon Column Observing Network), is expected in Level 2 retrievals. The key changes to the L2 algorithm include scaling the O2-A band spectroscopy (reducing XCO2 bias by 4 or 5 ppm); using interpolation with the instrument lineshape [ ILS ] (reducing XCO2 bias by 1.5 ppm); and fitting a zero level offset to the A-band. Users have to also carefully familiarize themselves with the disclaimer in the new documentation. An important element to note are the updates on data screening. Although a Master Quality Flag is provided in the data product, further analysis of a larger set of data has allowed the science team to provide an updated set of screening criteria. These are listed in the data user's guide, and are recommended instead of the Master Quality Flag. Lastly, users should continue to carefully observe and weigh information from three important flags: "warn_level" - Provides a value that summarizes each sounding's acceptability to a larger set of quality filters. A high warn level predicts that the sounding would fail most data filters applied to it. A low warn level suggests that the sounding would pass most quality filters that might be applied. "sounding_qual_flag" - quality of input data provided to the retrieval processing "outcome_flag" - retrieval quality based upon certain internal thresholds (not thoroughly evaluated) "master_quality_flag" - four possible values: "Good", "Caution" and "Bad", and "Failed", as determined from other flags in the L2 productThe short name for this data type is ACOS_L2S.
  • Version Description
    Not provided

Data Identification Fields:

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    Data Dates
    Creation
    Last Revision
    Processing Level

    2

    Quality
    These data are from algorithm build version 7.3
    Collection Progress

    Complete

    Use Constraints
    Global Carbon Cycle
    Access Constraints

    This product have full public access

Related URLs
    Science Keywords
    • EARTH SCIENCE
    • ATMOSPHERE
    • ATMOSPHERIC CHEMISTRY
    • CARBON AND HYDROCARBON COMPOUNDS
    • CARBON DIOXIDE
Other Descriptive Keywords
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Ancillary Keywords
  • EOSDIS
ISO Topic Categories
  • IMAGERY/BASE MAPS/EARTH COVER
Additional Attributes
  • Granularity
    STRING
    The time coverage of individual data granules.
    Resolution Range Begin Range End Unit of Measure Accuracy

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Acquisition Information Fields:

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Platforms
  • Earth Observation Satellites
    GOSAT
    Instruments
    • TANSO-FTS
Projects
Project Short Name Campaigns Project Dates
OCO No campaigns listed. No dates provided.

Temporal Information Fields:

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Spatial Information Fields:

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Location Keywords
    • GEOGRAPHIC REGION
    • GLOBAL

Data Centers

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  • NASA/GSFC/SED/ESD/GCDC/GESDISC
    ARCHIVER
    Goddard Earth Sciences Data and Information Services Center (formerly Goddard DAAC), Global Change Data Center, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA

    This data center does not have any addresses listed.

    This data center does not have any contact mechanisms listed.

Data Contacts

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  • ANDREY
    Metadata Author
    ANDREY SAVTCHENKO

    Distributed Active Archive Center Global Change Data Center
    Code 610.2
    NASA Goddard Space Flight Center
    Greenbelt, MD 20771

    • Email
    • 301-614-5705
    • 301-614-5268
  • Data Center Contact
    GES DISC HELP DESK SUPPORT GROUP

    NASA/GSFC/SED/ESD/GCDC/GESDISC

    Goddard Earth Sciences Data and Information Services Center
    Code 610.2
    NASA Goddard Space Flight Center
    Greenbelt, MD 20771

    • Email
    • 301-614-5224
    • 301-614-5268

Collection Citations Fields:

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    Collection Citations