NPP FTP Server Help
CLASS provides daily tar files containing publicly available NPP products (excluding the Raw Data Records) for easy anonymous FTP download at:
ftp://ftp-npp.class.ngdc.noaa.gov/
Files are organized into sub-folders by date, family, and datatype in this format:
ftp://ftp-npp.class.ngdc.noaa.gov/<Date>/<Family>/<Datatype>/
- The "Date" is in YYYYMMDD format and contains all datasets which have a starting observation date/time on this day. The most current 90 days of data will be retained give or take a day or two.
- The "Family" is the name of the datatype family as seen in the CLASS search box in parenthesis at the end of the description. It will usually be the name of the instrument (i.e. VIIRS, etc.)
- The “Datatype” is the name of the product found on the CLASS data Family search page:
For example, all VIIRS Imagery Band 01 EDR files from 2012/08/20 can be downloaded from this directory:
ftp://ftp-npp.class.ngdc.noaa.gov/20120820/VIIRS/VIIRS-Imagery-Band-01-EDR/
As CLASS receives the NPP datasets, they are individually compressed into a standard "gzip" format and "tar"-ed together in batches of less than 2 GBs for easy download. A sequence number suffix is added to the end to designate that they are a set of files. You will recognize the product name from the CLASS data Family search page. For the current Datatype example, users will see the following in the datatype sub-directory:
VIIRS_VIIRS-Imagery-Band-01-EDR_20120820_00001.tar
VIIRS_VIIRS-Imagery-Band-01-EDR_20120820_00002.tar
VIIRS_VIIRS-Imagery-Band-01-EDR_20120820_00003.tar
CLASS also produces a XML manifest of the datasets contained within each tar, which is stored in the same directory and similarly named:
VIIRS_VIIRS-Imagery-Band-01-EDR_20120820_00001.manifest.xml
VIIRS_VIIRS-Imagery-Band-01-EDR_20120820_00002.manifest.xml
VIIRS_VIIRS-Imagery-Band-01-EDR_20120820_00003.manifest.xml
Tags within these manifests designate the dataset names (<FileName>), file size in bytes (<FileSize>), and MD5 checksum (<FileChecksum>), among other information for the tar file itself such as the total uncompressed dataset volume (<UnCompressedFileVolume>) and the tar MD5 checksum to ensure integrity (<TarChecksum>).
Some datatypes may also have related geolocation data. These geo files are provided in their own separate datatype directory for that day, but for user convenience we have placed a directory link in the main datatype directory.
If you are interested in receiving automated notification of new tar files, we provide RSS feeds by datatype at:
http://download.class.ngdc.noaa.gov/download/FTP-NPP-RSS/by_type/<Datatype>.xml
As in the previous example, all provided VIIRS 01 EDRs are given through this feed file:
http://download.class.ngdc.noaa.gov/download/FTP-NPP-RSS/by_type/VIIRS-Imagery-Band-01-EDR.xml
You can add the URL to this XML file to any standard RSS reader software to receive a list of all currently-available files on the FTP server, and receive continual updates as new ones are added.