Introduction

The Global Data Service provides in near real-time products to the user community generated from instrument data. All instrument data recorded during the last orbit of Metop are dumped to the Central Data Acquisition Station (CDA) located on the island of Spitsbergen in Svalbard. The time to complete one orbit is about 102 minutes, which implies that Metop will make a little more than 14 orbits per day. The data received at the CDA is transferred to the EPS Core Ground Segment (CGS) located in EUMETSAT headquarters in Darmstadt, Germany, where it is processed for distribution via EUMETCast.

Global data products originating from the NOAA spacecraft will also be generated in the EPS CGS and disseminated via EUMETCast.

Service Description

Product Processing - Global data products are categorised according to instrument and product level. The following is a definition of the different product levels, as understood in the EPS context:

Level 0: Raw data after restoration of the chronological data sequence for each instrument, i.e. after demultiplexing of the data by instrument, removal of any data overlap due to the data dump procedure and relevant quality checks. Raw instrument data information (telemetry packets) is maintained during this process.

Level 1a: Instrument data in full resolution with radiometric and geometric (i.e. Earth location) calibration computed and appended but not applied.

Level 1b: Calibrated, earth located and quality controlled product, in the original pixel location, and packaged with needed ancillary, engineering and auxiliary data.

Level 1c: In the case of the IASI spectra, level 1b data after application of the apodization function.

Level 2: Earth located values converted to geophysical parameters, at the same spatial and temporal sampling as the level 1b and 1c data.

Level 3: Gridded point geophysical products on a multi-pass basis, or resampled products. Level 3 data (and in many cases level 2 data ) are generated by the various SAFs.

Product Dissemination Units (PDUs)  - Data granules generated for dissemination are Product Dissemination Units (PDUs), containing about 3 minutes of instrument-specific observation data. PDUs are independent, self-standing entities, i.e., not just slices of a full orbit product. The timeliness requirement for PDUs is 2 hours 15 mins (delta between sensing and reception at a EUMETcast station) for Level 1 products, and 3 hours for Level 2 products. PDUs are disseminated in the EPS native format and/or in BUFR format, depending on the instrument and processing level.

EPS Native Format and BUFR Format - PDUs in EPS native format are structured in sections:

• Header Section providing general data
• Pointer Section allowing navigation within the product file
• Global Aux Data Section defining data used in the processing for the entire product
• Variable Aux Data Section defining data used in the processing for part of the product
• Body Section containing the measurement data itself

See also the EPS Generic Product Format Specification.

BUFR is a WMO data representation form for global exchange of data in an unambiguous and efficient way, used for observations and satellite products. The main features are:

• Table driven code
• Data are self-defining (type, content, lengths etc.)
• Data are binary, so not readily human readable
• Supporting data compression
• Processing software is widely available (free download)

The BUFR tables used at EUMETSAT are the WMO Standard BUFR tables and are available at the .

Software Tools - Several software tools have been developed by EUMETSAT, in order to support the development of the EPS MCC and to help users in their handling of EPS Global Data. They are freely available and can be downloaded from. The main tools are:

• EPSView:A tool for visualization of EPS Products and analysis of correctly formatted PDUS and Full Orbit Products
• KAI: Takes as input EPS Products (a series of PDUs) and produces as outputs either display text, Full Orbit Products or individual records, depending on the options/configuration used

Dissemination

Global Products and Formats on EUMETCast - All Level 1 and Level 2 products will be made available via EUMETCast in Ku-band Europe. In addition, the Level 2 products will be made available in C-band Africa. The format of the Level 1 and Level 2 products distributed via EUMETCast are depicted in the following table:

EUMETCast File Naming Convention

For a description of the EUMETCast file naming convention, please see the document (PDF, 184 KB).

Dissemination of Metop data via the Global Telecommunication System

The abbreviated headers used for global level 1b, level 1b and level 1c data can be found on the respective instruments product pages.

Access and Registration

To access Metop global level 1 data, users are requested to register with the User Service Helpdesk, see .

For further detailed technical information on the EPS system please consult the availableset ofand.