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CIMSS is pleased to announce the release of the International ATOVS Processing Package (IAPP), version 2.01. The software operates in the Unix environment on IBM, SGI, and Sun workstations. Documentation is included with the software, describing how to install the IAPP, the design structure, and how each module operates.
The IAPPv2.01 is designed to work with the AAPP (AVHRR and ATOVS
Preprocessing Package) HIRS-3 level 1-D output file. The AAPP must be acquired independently from EUMETSAT. For information on AAPP, see http://www.eumetsat.de/en/ then click in the left frame on Programmes Under Development and EUMETSAT Polar Systems (EPS).
Below is a short description of the IAPP contents, licensing issues, and how to receive the package.
IAPP Contents
The IAPP currently uses radiances from HIRS-3, AMSU-A, and AMSU-B on NOAA-15, -16, and -17, preprocessed into the AAPP 1-D format, for retrieval. Ancillary data inputs for retrieval are high resolution topography (supplied), surface observations (see below) and numerical model data (see below). The IAPP performs temperature and moisture retrieval calculation on a 3x3 HIRS field of view (fov) matrix, or field-of-regard (FOR). HIRS and AMSU-A radiances are used for clear/cloudy fov determination. Depending on clouds, a HIRS + AMSU-A + AMSU-B retrieval, an AMSU-A + AMSU-B (i.e., no-HIRS) retrieval, or no retrieval is made for each FOR. The output file is in NetCDF format. Detailed information is provided in the documentation.
Surface data in the WMO Metar format is used, if available, to improve surface condition definition. If surface observations are not available, numerical model data is used (see next item) to define surface conditions, or, with neither available, window channel radiances are used to best approximate surface conditions. We strongly recommend using Metar surface information and/or NWP output to better describe surface conditions in retrieval processing.
Numerical model output can be used as a first guess field for the atmosphere and surface. Any model can readily be adapted to fit into the IAPP retrieval scheme. Clearly written documentation makes this task relatively straightforward. Alternatively, a regression scheme, based on synthetic radiance calculations, can be used to provide a first guess. Again, detailed information is provided in the documentation.
Licensing
As stated at the International TOVS Working Group meeting in Boulder, CO in February 1999, the IAPP source code will be provided to ITWG members. This software will have licensing restrictions similar to ITPP, in that you can use it at your site, but cannot re-distribute any portion of the software. For research and educational use, the IAPP should be considered as shareware/freeware. CIMSS has spent over $150,000 U.S. in developing IAPP; the funding came from ITPP licensing revenue. Continued development of the IAPP will continue to require new funds from licensing the IAPP. If you request to receive the IAPP for research or education purposes, a ITWG member license will be sent to you, along with a non-binding invoice for $3,000. If you can contribute to the IAPP development, use this invoice with your administration to send payment to CIMSS (shareware). If you cannot contribute to IAPP development, do nothing with the invoice, and consider the software to be freeware.
Obtaining IAPP
Send an email to me at thomas.achtor@ssec.wisc.edu requesting the current release of IAPP. We will respond with an ftp address and instructions to download the package, which amounts to about 35 mb. If you cannot obtain the IAPP via ftp, we can send you the package on CD-ROM, but it will take a week or two longer.
Thomas H. Achtor
Cooperative Institute for Meteorological Satellite Studies
Space Science and Engineering Center
University of Wisconsin - Madison
Phone 608-263-4206
Fax 608-262-5974
Email thomas.achtor@ssec.wisc.edu
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