Satellite
SSSP banner

Direct Broadcast

The purpose of this page is to identify and inform the international community about active High Resolution Picture Transmission (HRPT) receipt/product facilities, and to facilitate access/exchange of data (like EUMETSAT ATOVS Retransmission Service (EARS)) for sounding applications.

HRPT sites   |   Operational NOAA Polar Satellites   |   Research Satellites   |   Future Satellites   |   RARS   |   EARS

Operational NOAA Polar Satellites

To complement the global dumping of the whole orbit in Fairbanks for global data processing, instrument observations from NOAA polar orbiting weather satellites are transmitted to the ground via two different methods:
  • a transmission called Automatic Picture Transmission (APT) at a reduced resolution for the AVHRR sensor in analogic mode mainly for image display.
  • a direct broadcast called High Resolution Picture Transmission (HRPT), with data transmitted in real-time to ground stations as they are collected (at full resolution for all the instruments, approximately ten times the APT resolution for AVHRR). This system is for users who have established their own direct readout receiving station.

The direct broadcast system is useful for users who want to monitor a local geographical area, but with a good spatial resolution, geophysical parameters such as cloud cover and type, surface information, and/or provide atmospheric profiles within a short time delay (i.e., for meso-scale NWP assimilation).

The figure below gives an example of the acquisition area of the Meteo-France HRPT station in Lannion (west coast of France). The figure shows three successive orbits for AMSU-B1 local acquisition, NOAA16.

Three successive orbits for AMSU-B1 local acquisition
Click for larger version

The METOP system is Europe’s first polar-orbiting satellite dedicated to operational meteorology. It is a series of three satellites to be launched sequentially over 14 years starting in October 2006. METOP is equipped with the LRPT and HRPT direct broadcast facilities. In cooperation with EUMETSAT and CNES, the AAPP ATOVS package to include the pre-processing of the Infrared Atmospheric Interferometer Sounder (IASI) data and of the scientific supports (i.e., fast forward models, cloud detection, bias tuning, correlated errors). AAPP will not be able to process the other METOP instruments, i.e., GRAS, GOME, ASCAT, etc.

Processing packages
Several packages specific for the treatment of HRPT data exist. We indicate here a selection of them developed for operational purposes and which are freely available by request. These packages are currently maintained.

Level1
The AAPP pre-processing package is available by request to the NWP SAF at http://www.metoffice.gov.uk/research/interproj/nwpsaf/aapp/index.html. It performs the decommutation of the instrument data from the HRPT data frame, the data calibration, navigation and pre-processing, the mapping of the sounder instruments data on a common instrument grid (e.g., HIRS FOVs) and derives a set of parameters from the AVHRR data in the HIRS FOVs (i.e., cloud cover, surface temperature, etc.). The resulting outputs are archived in level1b (EUMETSAT definition), level1c and level1d formats.

Level2
The following IAPP package, designed to reconstitute the vertical structure of the atmosphere in terms of temperature and moisture in an operational way, is interfaced with the output files of the AAPP package (you must acquire AAPP independently from EUMETSAT). IAPP is developed by CIMSS. To download the package, or to see a short description of the IAPP contents and licensing issues, visit  http://cimss.ssec.wisc.edu/opsats/polar/iapp/IAPP.html

A possibility exists for HRPT data to interface the AAPP package with the SAF-NWP 1DVar packages, available at http://www.metoffice.gov.uk/research/interproj/nwpsaf/ .

Back to top