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    • TRMM Visible and Infrared Scanner Calibrated Radiances L1B 1.5 hours V7 (TRMM_1B01) at GES DISC

    Metadata Updated: April 11, 2025

    This TRMM Visible and Infrared Scanner (VIRS) Level 1B Calibrated Radiance Product (1B01) contains calibrated radiances and auxiliary geolocation information from the five channels of the VIRS instrument, for each pixel of each scan. The data are stored in the Hierarchical Data Format (HDF), which includes both core and product specific metadata applicable to the VIRS measurements. A file contains a single orbit of data with a file size of about 95 MB. The EOSDIS "swath" structure is used to accommodate the actual geophysical data arrays. There are 16 files of VIRS 1B01 data produced per day.

    For channels 1 and 2, Level 1B radiances are derived from the Level 1A (1A01) sensor counts by computing calibration parameters (gain and offset) derived from the counts registered during space and solar and/or lunar views. New calibration parameters are produced every one to four weeks. Channels 3, 4, and 5 are calibrated using the internal blackbody and the space view. These calibration parameters, together with a quadratic term determined pre-launch, are used to generate a counts vs. radiance curve for each band, which is then used to convert the earth-view pixel counts to spectral radiances.

    Geolocation and channel data are written out for each pixel along the scan, whereas the time stamp, scan status (containing scan quality information), navigation, calibration coefficients, and solar/satellite geometry are specified on a per-scan basis. There are in general 18026 scans along the orbit pre-boost and 18223 post-boost, with each scan consisting of 261 pixels. The scan width is about 720 km pre-boost and 833 km post-boost.

    Changes in horizontal resolution resulting from the TRMM boost that occurred on 24 August 2001:

    Pre-Boost (before 7 August 2001): Temporal Resolution: 91.5 min/orbit ~ 16 orbits/day; Swath Width: 720 km; Horizontal Resolution: 2.2 km

    Post-Boost (after 24 August 2001): Temporal Resolution: 92.5 min/orbit ~ 16 orbits/day; Swath Width: 833 km; Horizontal Resolution: 2.4 km

    Access & Use Information

    Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

    Downloads & Resources

    Dates

    Metadata Created Date November 12, 2020
    Metadata Updated Date April 11, 2025

    Metadata Source

    Harvested from NASA Data.json

    Other Data Resources

    Additional Metadata

    Resource Type Dataset
    Metadata Created Date November 12, 2020
    Metadata Updated Date April 11, 2025
    Publisher NASA/GSFC/SED/ESD/GCDC/GESDISC
    Maintainer
    Identifier C1282110251-GES_DISC
    Data First Published 2011-07-01
    Language en-US
    Data Last Modified 2025-03-31
    Category TRMM, geospatial
    Public Access Level public
    Bureau Code 026:00
    Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
    Schema Version https://project-open-data.cio.gov/v1.1/schema
    Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
    Harvest Object Id fc59cabb-4089-4f5e-9853-6c2005cb54bd
    Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
    Harvest Source Title NASA Data.json
    Homepage URL https://cmr.earthdata.nasa.gov:443/search/concepts/C1282110251-GES_DISC.html
    Metadata Type geospatial
    Old Spatial -180.0 -38.0 180.0 38.0
    Program Code 026:001
    Source Datajson Identifier True
    Source Hash d682c944d057e01f72054f183ab7e43d2712219054f90e090c420bf7f79d3628
    Source Schema Version 1.1
    Spatial
    Temporal 1997-12-20T00:00:00Z/2014-03-21T23:59:59.999Z

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