Frequently Asked Questions

This page answers questions that are sometimes asked by AAPP users. They may be only indirectly related to AAPP, therefore are not appropriate for the main AAPP documents.

Questions for other users and developers can be posted on the AAPP Forum or you can contact the developers via the Helpdesk.

  1. Where can I find out about other level 1 processing packages?

    The ITWG Working Group on Products and Software maintains a list at http://cimss.ssec.wisc.edu/itwg/pswg/software_packages.html. This also provides some tips (in an appendix) about working with raw data in CADU format.

  2. Is it possible to run AAPP in a Container?

    We are grateful to Liam Gumley for providing instructions on building AAPP in a Singularity container.

    Note that the workflow below is designed to be run by an ordinary (i.e., non-root) user. The only special requirement is that the user must have sudo permission to build the Singularity container. No special permissions are require to test or deploy the Singularity container.

    1) Download the README and tar files from ftp://ftp.ssec.wisc.edu/pub/gumley/aapp_singularity into a new directory of your choice
    2) Unpack the tar files
    3) Read the top-level README and follow the instructions

  3. How can I produce quick-looks from raw AVHRR data (CADU or HRPT)?

    If you are working with Metop data in CADU format, you can use the cadu_to_ccsds and ccsds_displayer tools that are part of EUMETSAT’s Metopizer software. Use the –image-avhrr option of ccsds_displayer to produce output in tiff or jpeg. These images are unprojected.

    if you are working with NOAA HRPT data, we are not aware of a ready-made display tool, but you can make your own (e.g. in Python or IDL) bearing in mind that the HRPT format is simple: the frame length is 11090 words and the raw AVHRR data are in words 751 to 10990 (5 channels x 2048 pixels). A word is 10 bits as it comes down from the satellite, but front-end systems often unpack this for you to give 16-bit words.

  4. How can I use local BUFR tables with ecCodes and/or Metview?

    The AAPP level 1d BUFR formats use local BUFR tables, which are included as an AAPP data file. These formats are not intended for international exchange, but they are used (for example) by UM partners. For running ecCodes utilities such as bufr_dump and bufr_filter, you can set the following environment variable:
    export ECCODES_DEFINITION_PATH=$(codes_info -d):$AAPP_PREFIX/AAPP/data/tools_eccodes/definitions

    Level 1D BUFR files can be visualised directly in Metview if you first define the evironment variable:
    export METVIEW_EXTRA_GRIB_DEFINITION_PATH=$AAPP_PREFIX/AAPP/data/tools_eccodes/definitions