Part of the International MODIS/AIRS Processing Package (IMAPP)
July 23, 2008: Version 5.2.1 released
The polar-orbiting Aqua spacecraft, launched by NASA in May 2002, provides an X-band direct broadcast service where data from all science instruments is downlinked to the Earth in near real-time. The AIRS/AMSU/HSB Processing Package for Direct Broadcast allows any ground station capable of receiving direct broadcast from Aqua to produce calibrated and geolocated AIRS, AMSU, and HSB Level 1B (calibrated and geolocated instrument observations) and Level 2 (geophysical retrieval) products.AIRS Direct Broadcast v5.2.1 is a special v5 delivery to allow Level-2 retrievals to be performed even though one of the AMSU-A channels it relies upon has degraded seriously. It compensates by replacing the noisy AMSU-04 channel with a synthetic channel made via regression from other AMSU-A channels. This package (v5.2.1) is functionally identical to the operational AIRS/AMSU/HSB software running at the GSFC DAAC (v5.2.2), with the following additions:
This package was developed by the
AIRS Team at NASA
Jet Propulsion Laboratory.
Distribution and support is provided by the Space
Science and Engineering Center at the University
This is a binary-only release for Intel Linux platforms. No source code is included. This version of the package has been tested on the following platforms:
The input expected by the package is Level 0 AIRS,
AMSU, HSB, and GBAD files, defined as reconstructed time-ordered CCSDS packets with
all communication artifacts (including duplicate and bad packets) removed.
This includes PN and Reed Solomon decoding as well as reassembly of the raw
telemetry packets. Processing of the data stream to this stage is the responsibility
of the user. Data in this format is known as a Production Data Set (PDS).
The Direct Readout Laboratory at NASA GSFC has developed a software application named RT-STPS (Real-Time Software Telemetry Processing System), which synchronizes the data, performs PN and RS decoding and packet reassembly, and writes the output in PDS format. This package is know to be compatible with Level 0 PDS files created by RT-STPS. In addition, many X-band ground station vendors supply processing hardware and/or software that creates compatible Level 0 files.
Installation and Operation
The package is available for download through the IMAPP download page
Please see the README file for instructions on
installing and running the package. If you are unable to download the package
because of a slow Internet connection, please contact us and we will arrange
to ship the package to you on DVD media. This package is released
under the terms of a NASA GSFC
Release and Usage Agreement.
The format of the AIRS, AMSU, and HSB Level 1B and Level 2 output
files is identical to the format of the equivalent GSFC DAAC files.
The format is HDF-EOS, and all ECS metadata fields are present. Regardless
of the size of the direct broadcast pass, the output files will be split
into standard AIRS 6-minute granules. Therefore the leading and/or trailing
granules created from a direct broadcast pass will contain some missing data.
This package was developed at NASA Jet Propulsion Laboratory by Quyen Nguyen,
Richard Forrister and Evan Manning.
This package is supported at SSEC by Liam Gumley, Allen Huang, and Kathy Strabala, as part of the International MODIS/AIRS Processing Package (IMAPP).
Related Links for AIRS/AMSU/HSB
Level 0 data:
Univ. of Wisconsin | NASA GSFC
Level 1B and Level 2 data:
Univ. of Wisconsin | GSFC DAAC Data Pool
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