Current version:<\/strong> v8.15, July 2025<\/small> As its main output, AAPP produces files of quality-controlled brightness temperature or radiance data for each instrument – either separately or mapped to a common field of view. An AVHRR cloud mask can also be generated. If profiles of atmospheric variables are required, the AAPP can be used in conjunction with an inversion package. AAPP radiance data are also used directly as input to variational data assimilation systems<\/a> at several leading centres for Numerical Weather Prediction.<\/p>\n AAPP development is closely linked to the activities and recommendations of the International TOVS Working Group (ITWG<\/a>).<\/p>\n Questions for other users and developers can be posted on the AAPP Forum<\/a>.<\/p>\n AAPP performs end-to-end processing of Sounding and Imager Data from the HRPT (High Resolution Picture Transmission) direct readout data stream of the TIROS-N\/NOAA<\/a><\/i> satellites and also their successors of the NOAA-KLM<\/a><\/i> satellite series, from 1998 onwards. AAPP also processes data from the European METOP<\/a><\/i> satellites.<\/p>\n Data from the following instruments can be processed:<\/p>\n For NOAA satellites, AAPP performs the following tasks:<\/p>\n For METOP, AAPP ingests “EPS Level 0” files (one file per instrument), then performs navigation, calibration and pre-processing as above.<\/p>\n In the case of IASI, level 1 processing is performed by the OPS-LRS (Operational Software – Local Reception Station), which is an optional extension to AAPP and is based on the OPS software provided to EUMETSAT by CNES.<\/p>\n For NPP, the starting points for AAPP are Sensor Data Record files (SDR). For direct readout, you will need an external program, such as University of Wisconsin’s CSPP package, or NASA’s IPOPP package, to generate the SDR files. The same applies to FY-3, for which the China Meteorological Administration provide a processing package for direct readout use.<\/p>\n
\n\nThe ATOVS and AVHRR Pre-processing Package (AAPP) is supplied and maintained by the NWP SAF. This package processes data from instruments on board the NOAA POES<\/a> polar orbiting satellites – namely HIRS, AVHRR, AMSU and MHS<\/a> – and from HIRS, AVHRR, AMSU, MHS and IASI<\/a> on the European METOP<\/a> satellites. For these satellites AAPP can ingest and process raw direct readout data. It also processes Sensor Data Record data from the new-generation Suomi NPP satellite, and from the sounders on the Chinese FY-3 satellites. Support for ESA’s Arctic Weather Satellite mission was added in 2025.<\/p>\nSupported Instruments<\/h2>\n
TIROS\/NOAA satellites<\/h3>\n
TIROS-N<\/h4>\n
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NOAA-KLM<\/h4>\n
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NOAA-NN’<\/h4>\n
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MetOp Satellites<\/h3>\n
MetOp<\/h4>\n
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Other Satellites<\/h3>\n
NPP<\/h4>\n
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FY3<\/h4>\n
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Arctic Weather Satellite<\/h4>\n