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International MODIS/AIRS Processing Package

 AIRS L1B HDFEOS to BUFR Format Utility v1.1 Release        22 September 2009

   This package consists of software that will convert AIRS Level 1B Radiance HDFEOS files (AIRS.2009.02.06.176.L1B.AIRS_Rad.v5***.hdf) into Binary Universal Form for the Representation of meteorological data (BUFR) format. The output consists of selected channels at full spatial resolution. The software defaults to selecting the standard 324-channel set, but the user can substitute their own channel selection if you prefer.

This software was written by Nigel Atkinson, Met Office, Exeter, UK. The changes to this package from version 1.0 are:

  • Bug fixes:

    Aqua satellite ID changed from 874 to 784. Start orbit set to missing when the level 1b file contains 65534. Wavenumber unit changed from cm^-1 to m^-1 in accordance with BUFR tables. Satellite height unit changed from km to m in accordance with BUFR tables. Time stamps changed from TAI93 to UTC. The difference is 7 seconds in 2009. Wavenumber changed to 1b "nominal_freq" instead of "spectra_freq", as recommended in the comments in the 1b format definition.

  • New processing options and environment variables:

    • AIRS_MINIMUM_SCANS (default 20) If a granule has fewer scans than this then it will not be processed because the calibration is likely to be unreliable (recommended by Evan Manning, JPL).
    • AIRS_SKIP_SCANS (default 6) Number of scans to skip at start and end of an overpass. The calibration is unreliable for these scans. Since granules are encoded independently, if there are missing scans at the start of a granule then the first good scan is taken to be the start of an overpass. Similarly at the end.
    • USE_DUMMYVALUES Can be set to Y to insert dummy lat/lon/time if they are missing

This software encodes AIRS 1b files into BUFR using the same BUFR template as is used in the NOAA/NESDIS near real-time processing, (see http://www.star.nesdis.noaa.gov/smcd/spb/iosspdt/iosspdt.php).

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