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Data Volume

The MODIS Cloud Mask Product (MOD35_L2) will be produced at the MODAPS facility at the NASA Goddard Space Flight Center. MODAPS will produce 100% of the MOD35_L2 product. MOD_PR35 process executes 24 hours a day (on every MODIS L1B granule).

Approximately 288 MOD35_L2 HDF files are produced per day. Each HDF file is roughly 47.5 MB in size, so the total data volume is approximately 13.7 GB per day.

Production Rules

The MOD35_L2 process is run when all required input data files are available. The process shall not be delayed in an attempt to acquire optional files that are not available at the scheduled run time. The input files (both required and optional) for each MOD35_L2 process execution are:

  • Input MODIS Files

    1. One granule of 1 kilometer Level-1B data (required)
    2. One granule of the geolocation product, MOD03 (required)
    3. One granule of 250 meter Level-1B data (optional)

  • Input Ancillary Files

    1. NCEP daily global sea ice concentration from SSM/I on 0.5 degree grid in GRIB format (optional)
      ftp site
    2. NCEP GDAS1 6-hourly global meteorological data on a 1 degree grid in GRIB format (optional)
      ftp site
    3. NCEP daily global total ozone from TOVS on a 1 degree grid in GRIB format (optional)
      ftp site
    4. NCEP weekly global Reynolds sea surface temperatures on a 1 degree grid in ASCII format (optional)
      ftp site
    5. NSIDC daily global ice concentration and snow extent from SSM/I on 721x721 N/S Hemisphere azimuthal grids in HDF/EOS format (optional)
      nsidc web site

      The GRIB files are available four times per day, so the closest time period to data should be staged. If the data is not available, the process should be run without it.

  • Input Static Files

    1. 1km Olson global ecosystem map (required)
    2. MOD_PR35 thresholds.dat file, which contain the processing path spectral test thresholds which are the heart of the cloud mask processing software. (required)

      Since processing cannot be initiated until these files are staged, the 10 minute global ecosystem map is to be used as a backup to the 1km Olson global file.

  • Output Product Files

    1. MODIS Cloud Mask Product (MOD35_L2) in Hierarchical Data Format (HDF)
    2. Quality Control file in ASCII format
    3. Granule-based clear radiance file in Hierarchical Data Format (HDF)

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