DBNet

For background on the DBNet project, see the WMO DBNet page.

The aim of DBNet is to provide near real-time access to near-global data from Low Earth Orbit (LEO) satellites, in order to meet in a cost-efficient manner the timeliness requirements of regional and global Numerical Weather Prediction (NWP) and other applications.

When satellites have a Direct Broadcast capability, which is the case of most LEO meteorological satellites, an alternative data access route is the acquisition of the Direct Broadcast data stream at a local ground station, which allows real-time acquisition, albeit with coverage limited to the portion of orbit within the area of visibility of the local station.

The Direct Broadcast Network for Near Real-Time Relay of LEO satellite data (DBNet) overcomes this limitation in offering a cost-efficient trade-off between coverage and timeliness. It coordinates data acquisition through a globally distributed network of local Direct Broadcast receiving stations, their processing in accordance with agreed standards, and their rapid delivery to the global user community through appropriate telecommunication systems.

Source: Guide to the Direct Broadcast Network, WMO

The NWP SAF routinely checks the quality of DBNet data and their consistency with globally received data. It is important for NWP centres to be assured of the high quality of the DBNet data so they can take advantage of the timeliness (within 30 min, compared to 1.5-7 hours for global data). DBNet data is used in both global models and regional models. It is particularly valuable for the regional models, which often have tight time constraints.

Local DBNet and Global data consistency monitoring

AMSU-A, MHS and HIRS (ATOVS)

For each of the ATOVS instruments, the local-global data comparison is made with the instrument level 1c data, on its native grid. Each regional DBNet centre runs AAPP to generate the level 1c local BUFR data which is compared with the corresponding global data files generated by the global processing centre (NOAA for NOAA satellites, EUMETSAT for Metop satellites).

IASI

DBNet IASI data are distributed with 500 channels (defined by EUMETSAT) and 300 Principal Component scores. An AVHRR cluster analysis is included in the product.

The local-global data comparison is performed using IASI level 1c data, on IASI’s native grid. The level 1c files are generated using AAPP (for calibration, geo-location and apodization) from the incoming level 1c regional BUFR data, and are compared with the corresponding level 1c files generated by the global processing centre (EUMETSAT).

In addition, Meteo-France have developed a dedicated web page for monitoring cloud fraction and brightness temperature on the IASI field of view, showing global maps versus local maps from Lannion data. See http://www.umr-cnrm.fr/nwpsaf/.

ATMS and CrIS

DBNet CrIS data are distributed with 431 channels defined by NOAA, in “full spectral resolution” mode (0.625 cm-1 spectral sampling for all three bands). Although the BUFR format includes provision for a VIIRS cluster analysis, the data values are currently set to missing.

For each of the instruments ATMS and CrIS, the local-global data comparison is performed using the instrument level 1c data, on its native grid. Each regional DBNet centre runs CSPP and AAPP to generate the level 1c BUFR data which is compared with the corresponding level 1c global data files generated by the global processing centre (NOAA).

MWHS-2 and MWTS-2/MWTS-3 (VASS) and MWRI

MWHS-2, MWTS-2 and MWRI are operating on FY-3D, and MWHS-2 and MWTS-3 on FY-3E. For each of the instruments, the local-global data comparison is performed using the instrument level 1c data, on its native grid. Each regional DBNet centre runs FY3DL0pp, FY3DL1pp and AAPP to generate level 1c BUFR data which is compared with the corresponding level 1c files generated by the global processing centre (CMA).

AIRS

A DBNet-AIRS service is operated by SSEC/NOAA/CIMSS, with 324 channels defined by NOAA and full spatial resolution. The AIRS service is not part of the NWP SAF monitoring. For details on how to access the data, see the list of bulletin headers and corresponding file names.

Timeliness monitoring

You can access information about the timeliness and availability of DBNet data via a Timeliness monitoring page. This is a preliminary service and will be undergoing developments in due course. Plots and statistics files are generated each day, based on the reception logs of the previous day. You can access plots for the last 7 days and also daily and weekly statistics such as number of passes, 50th and 90th centile for delay, etc. Some data are received by more than one reception route (e.g. GTS and ftp, as explained in more detail below); these are displayed in separate files.

Resources

Some external web sites providing information and monitoring facilities relevant to DBNet:
JMA Asia-Pacific RARS monitoring
Meteo-France observation monitoring
Australian Bureau of Meteorology
KMA DBNet monitoring
CIMSS timeliness monitoring for NOAA DBRTN stations
Instructions for building and running AAPP and CSPP in Singularity containers (courtesy of Liam Gumley, SSEC/UW/CIMSS)
GCMS Best Practices

GTS information

DBNet data are made available to the international community via various distribution mechanisms. For National Met Services of WMO Members, all operational DBNet data are available via WMO’s Global Telecommunications System (GTS). To allow users to identify bulletins of interest, we have compiled a list of bulletin headers and corresponding file names, based on information gathered from the NWP SAF monitoring. The page also includes a list of the station codes and identifiers (i.e. centre, cubcentre, originator, abbreviation).

Reception summary table

As well as GTS, some data are also distributed via mechanisms such as EUMETCast and internet ftp, sometimes including data that are candidates for GTS dissemination. The table below summarises the data currently monitored by the NWP SAF, and the route taken to get the data to the monitoring system that is hosted by the Met Office. The contents of the data (i.e. BUFR messages, generated by the originator) are not expected to be affected by the routing; sometimes there are small differences in timeliness (see the Timeliness monitoring section above).

Software packages

The table below lists the main software packages needed by a DBNet processing centre. Last updated 12/03/2024

For installation of AAPP, OPS-LRS and ancillary packages, see the install_aapp8.sh script, linked from AAPP downloads page. If you have any questions about software installation, please contact the NWP SAF Helpdesk.

For additional information on software packages, including hints on manipulation of CADU files, you may wish to consult this ITWG document