DBNet

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

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).

ATMS and CrIS

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, MWTS-2 and IRAS (VASS)

MWHS-2 and IRAS are operating on the FY-3C satellite; MWHS-2 and MWTS-2 are on FY-3D. 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 FY3[C,D]L0pp, FY3[C,D]L1pp and AAPP to generate level 1c BUFR data which is compared with the corresponding level 1c files generated by the global processing centre (CMA).

Resources

Some external web sites providing information and monitoring facilities relevant to DBNet:
JMA Asia-Pacific RARS monitoring
Meteo-France observation monitoring
ECMWF observation monitoring
Australian Bureau of Meteorology
KMA DBNet information
EUMETSAT EARS services

Reception summary table

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). 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; there may be small differences in timeliness and there are plans to quantify this.

Operational DBNet stations Route Instruments
All EARS stations EUMETCast ATOVS, IASI, ATMS, CrIS, VASS
All NOAA/SSEC stations EUMETCast ATOVS, IASI, ATMS, CrIS
Asia-Pacific – Papeete GTS ATOVS, ATMS, CrIS
Asia-Pacific stations – Australia and New Zealand ftp from BoM ATOVS
Asia-Pacific stations – Japan, Korea ftp from BoM ATOVS, IASI, ATMS, CrIS
Asia-Pacific stations – China, India ftp from BoM ATOVS
South America – Brazil ftp from Sao Paolo ATOVS, IASI, ATMS, CrIS
South America – Argentina ftp from Cordoba ATOVS, IASI
Other stations Route Instruments
Exeter: used as an independent reference ATOVS, IASI, ATMS, CrIS