6.
ASCAT Product Formats and Dissemination
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6.
ASCAT Product Formats and Dissemination |
A description of the dissemination means for EPS products and formats is provided in the following paragraphs, focusing down on ASCAT products and their formats.
Instrument and ancillary data acquired by the Metop satellites will be broadcast and received by authorised users in real-time via:
The data will be received by local reception stations. It is the responsibility of the user to procure and install a local reception station. Specification documentation for a EUMETSAT-based HRPT Reference User Station is available for information on the EUMETSAT webpage Metop - AHRPT.
The output format of the EUMETSAT HRPT Reference User Station is Level 0 products in the EPS Native format [RD11], [RD27].
The broadcast data are encrypted. To get authorisation to access the data, users need to register with the EUMETSAT User Services and will receive the data decryption information.
Data from the NOAA payload are also broadcast and received by local users via the HRPT mechanism. For details on the NOAA HRPT system, the reader is referred to the NOAA KLM User's Guide [RD47].
Global EPS products at different levels will be distributed
in near real-time via EUMETSAT's Data Distribution System (EUMETCast). EUMETCast
utilises the services of a satellite operator and telecommunications provider
to distribute data files using Digital Video Broadcast (DVB) to a wide audience
located within the geographical coverage zone which includes Europe, Africa
and the American continent. EUMETCast is part of a wider network known as GEONETCast,
with coverage also over Asia and Australia. For further information on EUMETCast
and GEONETCast, visit:
http://www.eumetsat.int/Home/Main/DataAccess/EUMETCast/index.htm?l=en.
Within the current EUMETCast configuration, the multicast system is based upon a client/server system with the server side implemented at the EUMETCast uplink site (Usingen, Germany) and the client side installed on the individual EUMETCast reception stations. The telecommunications suppliers provide the DVB multicast distribution mechanism. Data/product files are transferred via a dedicated communications line from EUMETSAT to the uplink facility. These files are encoded and transmitted to a geostationary communications satellite for broadcast to user receiving stations. Each receiving station decodes the signal and recreates the data/products according to a defined directory and file name structure. A single reception station can receive any combination of the provided services.
A typical EUMETCast reception station comprises a standard PC with DVB card inserted and a satellite off-set antenna fitted with a digital universal V/H LNB. In addition, users require the multicast client software, which can be obtained via the EUMETSAT User Services.
More detailed information on this service can be found in the EUMETSAT webpage EUMETCast Dissemination Scheme.
Products distributed on EUMETCast can be formatted in a variety of formats, including EPS native format and the WMO formats (BUFR and GRIB).
A subset of EPS products will be disseminated additionally in near real-time via the Global Telecommunication System (GTS). GTS is the World Meteorological Organization integrated network of point-to-point circuits, and multi-point circuits which interconnect meteorological telecommunication centres. Its purpose is to enable an efficient exchange of meteorological data and products in a timely and reliable way to meet the needs of World, Regional and National Meteorological Centres. The circuits of the GTS are composed of a combination of terrestrial and satellite telecommunication links. Meteorological Telecommunication Centres are responsible for receiving data and relaying them selectively on GTS circuits. The GTS is organised on a three-level basis, namely:
More detailed information on this service can be found on the WMO website www.wmo.int.
Products distributed on the GTS are in official WMO formats, namely BUFR or GRIB.
All EPS products and auxiliary data are normally archived and made available to users from the EUMETSAT Data Centre (formerly known as the UMARF or Archive Services) upon request.
The Data Centre can be accessed through the EUMETSAT webpage EUMETSAT Data Centre. Access is through a Web interface, the Online Ordering Application, through which the users are able to browse and order products, manage their user profile, retrieve products, documentation and software libraries, get help, etc.
The Data Centre features include geographical and time sub-setting and image preview. EPS products archived in the Data Centre can be accessed in a variety of formats, including EPS native format, HDF5 and in some cases also BUFR.
Table 6.1 summarises the different dissemination means and formats for all ASCAT products available to users.
| Format | Real-Time Direct Broadcast | Near-Real-Time dissemination on EUMETCast (timeliness) | Near-Real-Time dissemination on GTS (timeliness) | EUMETSAT Data Centre retrieval (timeliness) | OSI SAF FTP service (timeliness) |
| Metop raw data format | ASCAT HRPT raw data stream and Metop Admin message |
-- |
-- |
-- |
-- |
| EPS native format | -- | ASCAT Level 1b spatially averaged products (2 h 15 min) |
-- |
ASCAT Level 0 ASCAT Level 1b spatially averaged products ASCAT Level 1b full resolution product ASCAT Level 2 Soil Moisture (8-9 h) |
-- |
| HDF5 | -- |
-- |
-- |
ASCAT Level 0
ASCAT Level 1b spatially averaged products
ASCAT Level 1b full resolution product
(8-9 h) |
-- |
| WMO (BUFR) | -- |
ASCAT Level 1b spatially averaged products (2 h 15 min) ASCAT Level 2 multi-parameter (ocean winds and soil moisture) global (2 h 30 min) ASCAT Level 2 ocean winds regional (30 min) ASCAT Level 2 Soil Moisture (2 h 30 min) |
ASCAT Level 1b spatially averaged products (2 h 15 min) ASCAT Level 2 multi-parameter (ocean winds and soil moisture) global (only 25 km swath grid) (2 h 30 min) ASCAT Level 2 ocean winds regional (30 min) ASCAT Level 2 Soil Moisture (2 h 30 min) |
ASCAT Level 1b spatially averaged products (8-9 h) ASCAT Level 2 multi-parameter (ocean winds and soil moisture) global (8-9 h) |
ASCAT Level 2 multi-parameter (ocean winds and soil moisture) global
(2 h 30 min) ASCAT Level 2 ocean winds regional (30 min) |
| NetCDF | -- | -- | -- | ASCAT Level 2 ocean winds global (2 h 30 min) |
ASCAT Level 2 ocean winds global (2 h 30 min) |
'Timeliness' refers to the elapsed time between sensing and dissemination.
Table 6.1: Summary of dissemination means and formats for ASCAT products
Real-time broadcast of ASCAT raw data is not covered in this guide. It is noted though for information that the raw data streams mentioned in the table above indicate what is broadcast by the platform. Depending on the reception system used (i.e., the HRPT local reception system), different formats of this raw data stream are produced. This depends on the local reception station provider. For Metop HRPT stations, the Reference User Station has been developed to produce EPS Native Level 0 format products.
Although available through the EUMETSAT Data Centre, ASCAT Level 0 products are not considered an end-user product, hence they are not addressed in this guide either.
The ASCAT products disseminated to users in near real-time are:
The dissemination granularity of the data is 3 minutes for both Level 1b and Level 2 global products, and 25 min for Level 2 regional products.
The ASCAT products available from the EUMETSAT Data Centre are:
Reprocessed data corresponding to the above products are also available via the Data Centre.
All products are archived as full-dump products, but sub-setting capabilities are provided to the user in the retrieval step. The products are available for the users in the EUMETSAT Data Centre 8 to 9 hours after sensing. The static auxiliary data used in the generation of all products (see Section 3 for details) can also be found there.
6.3.1.1 General overview of the EPS generic product format
All products in EPS native format are structured and defined according to an EPS Generic Product Format. This format is not ASCAT specific. The general product section breakdown is given, and the following sections will focus on how this generic format is further applied to ASCAT products.
This description is not aimed at supporting the writing of reader software for the ASCAT or other EPS products, because readers and product extraction tools are already available (see Section 5). The intention of this and the following sections is to provide enough information to be able to use such available tools and to interpret the retrieved information.
For users interested in writing their own product readers for one or several ASCAT products in EPS native format, we refer them to the detailed format specifications provided in [RD11] and [RD12].
The general structure of the products is broken down in sections, which contain one or more records of different classes. Every single record is accompanied by a Generic Record Header (GRH), which contains the metadata necessary to uniquely identify the record type and occurrence within the product. The following general structure is followed by all EPS products, where all the sections occur always in the given order.
Header Section, containing metadata applicable to the entire product. The header section may contain two records, the Main Product Header Record (MPHR) and the Secondary Product Header Record (SPHR). This is the only section that contains ASCII records, the rest of the product is in binary.
Pointer Section, containing pointer information to navigate within the product. It consists of a series of Internal Pointer Records (IPR), which include pointers to records within the Global Auxiliary Data, Variable Auxiliary Data and Body Sections that follow.
Global Auxiliary Data Section, containing information on the auxiliary data that have been used or produced during the process of the product and applies to the whole length of the product. There can be zero or more records in this section, and they can be of two classes: Global External Auxiliary Data Record (GEADR), containing an ASCII pointer to the source of the auxiliary data used, and Global Internal Auxiliary Data Record (GIADR), containing the auxiliary data used itself.
Variable Auxiliary Data Section, containing information on the auxiliary data that have been used or produced during the process of the product and may vary within a product, but with a frequency in any case less than the measurement data itself. There can be zero or more records in this section, and they can be of two classes: Variable External Auxiliary Data Record (VEADR), containing an ASCII pointer to the source of the auxiliary data used, and Variable Internal Auxiliary Data Record (VIADR), containing the auxiliary data used itself.
Body Section, which is usually the main bulk of the product and contains the raw or processed instrument data and associated information. This section contains time-ordered Measurement Data Records (MDR). A particular type of MDR can occur to indicate the location of an unexpected data gap within any product, the Dummy Measurement Data Record (DMDR).
The format of the MPHR, IPRs, GEADR, VEADR and DMDRs is common to all products, while the other records can be of different formats and contents, and identified as of different sub-classes for different products. Every record consists of a series of fields, which can have different data types. See Appendix C for all possible data types.
It is important to note that GEADR and VEADR records are included in the products to support processing configuration control for EUMETSAT at product level. They point to the name of auxiliary data files used in the processing, but they are not of any interest or use to the end-user for the utilisation of the products.
Two types of records deserve special description, because they are key to navigating within the products, namely the GRH and the IPR. Their format and the meaning of their fields are detailed in Appendix D.
Table 6.2 gives an example of the general structure of the Generic Product Format.
| Section | RECORD CLASS | RECORD SUBCLASS | START TIME | STOP TIME | ||||||||||||||||||||||||||||||||||||||||||||||||
| HEADER SECTION |
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| INTERNAL POINTER SECTION |
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| GLOBAL AUXILIARY DATA SECTION |
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| VARIABLE AUXILIARY DATA SECTION |
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| BODY SECTION |
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Table 6.2: Generalised schematic of the generic product format
6.3.1.2 Granularity of the EPS products
The Full EPS product is produced by processing a dump of data. This is the product size used to archive in the EUMETSAT Data Centre.
In addition, the Regional EPS product is a full product that has been passed through a geographical filter. This may happen, for example, during the retrieval of the product from the Data Centre.
Finally, a Product Dissemination Unit (PDU) is the near-real-time dissemination of the full product, and it is typically of 3 minutes. A PDU is often referred to as a product 'granule'.
The EPS Generic Product Format has been defined to apply to any length of sensing. That means that the same generic format described above applies to a 3-minute duration granule, half an orbit or a full dump of data. The length in time of the product is contained in the MPHR.
6.3.1.3 Product format version control
Every record class and sub-class has an associated record version number contained in its corresponding GRH. In addition, each product has a format version number, which is stored in the MPHR.
6.3.1.4 Product naming convention
The file naming convention for EPS products in EPS native format provides a product name that uniquely identifies any product and provides a summary of its contents. The field contents in a product name correspond to those in the MPHR.
<INSTRUMENT_ID>_<PRODUCT_TYPE>_<PROCESSING_LEVEL>_<SPACECRAFT_ID>_
_<SENSING_START>_<SENSING_END>_<PROCESSING_MODE>_<DISPOSITION_MODE>_
_<PROCESSING_ TIME>
| Product Name Field / MPHR Field | Description | Size in Characters |
| INSTRUMENT_ID | Instrument identification | 4 |
| PRODUCT_TYPE | Product Type | 3 |
| PROCESSING_LEVEL | Processing Level Identification | 2 |
| SPACECRAFT_IUD | Spacecraft identification | 3 |
| SENSING_START | UTC Time of start of Sensing Data | 15 |
| SENSING_END | UTC Time of end of Sensing Data | 15 |
| PROCESSING_MODE | Identification of the mode of processing | 1 |
| DISPOSITION_MODE | Identification of the type of processing | 1 |
| PROCESSING_TIME | UTC time at start of processing for the product | 15 |
Table 6.3: EPS product name fields and their correspondence with MPHR fields
For the ASCAT products, the resulting product file names are as follows:
| Product | Product name |
| ASCAT Level 1b 25-km grid spacing | ASCA_SZO_1B_Mnn_< ...> |
| ASCAT Level 1b 12.5-km grid spacing | ASCA_SZR_1B_Mnn_< ...> |
| ASCAT Level 1b full resolution | ASCA_SZF_1B_Mnn_< ...> |
| ASCAT Level 2 Soil Moisture 25-km grid spacing | ASCA_SMO_02_Mnn_< ...> |
| ASCAT Level 2 Soil Moisture 12.5-km grid spacing | ASCA_SMR_02_Mnn_< ...> |
Table 6.4: Generic ASCAT product names
Records to be found in the ASCAT Level 1b products are in the following tables, each corresponding to a different product format version:
| Record name | Description | Usage | Subclass ID |
| MPHR | Main Product Header Record | Main product identification details | 0 |
| Necessary IPRs | Internal Product Record Pointers | Necessary to access directly different records in the product | 1-9 |
| GEADR_DK | Deblooming Kernels Internal File | Not relevant for end-user | 1 |
| VIADR-TR | Transponder parameters | 1 |
|
| VIADR-IP | Instrument parameters | 2 |
|
| VIADR-PP | Processing parameters | 3 |
|
| VIADR-OA | Orbit/attitude parameters | 4 |
|
| VIADR-DUMP | Dump Identification and other dump-related information | 5 |
|
| MDR-1B-25KM | Only used in Level 1b 12.5-km grid spacing products | Level 1b main product contents - They contain all the user needs for interpretation and further processing of the data, including relevant product quality information (see next sections for more details) | 1 |
| MDR-1B-50KM | Only used in Level 1b 25-km grid spacing products | 2 |
|
| MDR-1B-FULL | Only used in Level 1b Full products | 3 |
Table 6.5: Record types in ASCAT Level 1b product for product format version
10.0
| Record name | Description | Usage | Subclass ID |
| MPHR | Main Product Header Record | Main product identification details | 0 |
| SPHR | Secondary Product Header Record | Summary of product quality flags | 0 |
| Necessary IPRs | Internal Product Record Pointers | Necessary to access directly different records in the product | 1-9 |
| GEADR_OSV | Name of input auxiliary file containing orbit
parameters |
Not relevant for end-user | 1 |
| GEADR_LSM | Name of input auxiliary file containing land /ocean mask | 2 |
|
| VEADR-PRC | Name of input auxiliary file containing processing parameters | 1 |
|
| VEADR-INS | Name of input auxiliary file containing instrument parameters | 2 |
|
| VEADR-NTB | Name of input auxiliary file containing normalisation factors | 3 |
|
| VEADR-DEB | Name of input auxiliary file containing deblooming kernels | 4 |
|
| VIADR-OA | Orbit/attitude parameters | 4 |
|
| VIADR-VER | Summary of processor and auxiliary file configuration | 6 |
|
| MDR-1B-25KM | Only used in Level 1b 12.5-km grid spacing products | Level 1b main product contents - They contain all the user needs for interpretation and further processing of the data, including relevant product quality information (see next sections for more details) | 1 |
| MDR-1B-50KM | Only used in Level 1b 25-km grid spacing products | 2 |
|
| MDR-1B-FULL | Only used in Level 1b Full products | 3 |
Table 6.6: Record types in ASCAT Level 1b product for product format version 11.0
6.3.2.1 Level 1b spatially averaged products format
These products are organised as successive lines of nodes along track, referenced to by the orbit time that corresponds to that line of nodes (ref. [RD13]). The START/STOP times indicated in the MPHR and the corresponding VIADR's, are also referenced with respect to that time.
The Level 1b averaged products are organised:
Each MDR contains data of the three types, defining fields of three different dimensions. Associated data of the same dimensions, related for example to geometry or quality flags, are also included in the MDR.
The number of nodes in an ASCAT Level 1b product line depends on the resolution of the spatial averaging and the grid spacing between nodes. Every line of the 25-km grid spacing product will have 42 nodes (21 per swath). Every line of the 12.5-km grid spacing product will have 82 nodes (41 per swath). Every line contains data from both swaths, ordered from left swath to right swath and from left to right within the swaths, if one moves in the direction of the instrument.
The number of σ0 values in an ASCAT Level 1b product node is, as the name of 'triplet' indicates, three.
The occurrence of the different records in the Level 1b spatially averaged products is as follows:
| Record | Occurrence |
| MPHR | Once per product |
| IPRs | Once each per product |
| GEADR-DK | Once per product |
| VIADR-TR, -IP, -PP, -OA, -DUMP | Occurs at least once. Re-occurs each time the applicability of the information changes within the product. |
| MDR-1B-50KM, -25KM | Once per every line of nodes |
Table 6.7: Occurrence of records in ASCAT Level 1b spatially averaged product
for product format version 10.0
| Record | Occurrence |
| MPHR | Once per product |
| SPHR | Once per product |
| IPRs | Once each per product |
| GEADR-OSV, -LSM | Once per product |
| VEADR-PRC, -INS, -NTB, -DEB | Occurs at least once if the auxiliary file referred to has been used in the processing. Re-occurs each time the applicability of the information changes within the product. |
| VIADR-OA, -VER | Occurs at least once. Re-occurs each time the applicability of the information changes within the product. |
| MDR-1B-50KM, -25KM | Once per every line of nodes |
Table 6.8: Occurrence of records in ASCAT Level 1b spatially averaged product for product format version 11.0
See Section 10 for more details on the contents and format of the ASCAT Level 1b spatially averaged products.
6.3.2.2 Level 1b full-resolution product format
ASCAT Level 1b full resolution corresponds to σ0 values generated from individual echo samples within an echo line in a source packet, together with associated data, referenced by the echo source packet localisation time (T0, ref. [RD13]). The START/STOP times indicated in the MPHR and the corresponding VIADR's, are also referenced by the echo source packet localisation time T0.
The Level 1b full resolution product is organised per antenna beam firing sequence. Each MDR will therefore contain six fields of measurements containing the 256 geographically-localised σ0 values, plus associated data.
The occurrence of the different records in the Level 1b full resolution product is as follows:
| Record | Occurrence |
| MPHR | Once per product |
| IPRs | Once each per product |
| GEADR-DK | Once per product |
| VIADR-TR, -IP, -PP, -OA, -DUMP | Occurs at least once. Re-occurs each time the applicability of the information changes within the product. |
| MDR-1B-FULL | Once per every antenna beam firing sequence |
Table 6.9: Occurrence of records in ASCAT Level 1b full resolution product
for product format version 10.0
| Record | Occurrence |
| MPHR | Once per product |
| SPHR | Once per product |
| IPRs | Once each per product |
| GEADR-OSV, -LSM | Once per product |
| VEADR-PRC, -INS, -NTB, -DEB | Occurs at least once if the auxiliary file referred to has been used in the processing. Re-occurs each time the applicability of the information changes within the product. |
| VIADR-OA, -VER | Occurs at least once. Re-occurs each time the applicability of the information changes within the product. |
| MDR-1B-FULL | Once per every antenna beam firing sequence |
Table 6.10: Occurrence of records in ASCAT Level 1b full resolution product for product format version 11.0
See Section 11 for more details on the contents and format of the ASCAT Level 1b full resolution product.
Records to be found in the ASCAT Level 2 Soil Moisture products are shown in the following table:
| Record name | Description | Usage | Subclass ID |
| MPHR | Main Product Header Record | Main product identification details | 0 |
| Necessary IPRs | Internal Product Record Pointers | Necessary to access directly different records in the product | 1-3 |
| MDR-2-SM-25KM | Only used in Level 2 12.5-km grid spacing products | Level 2 main product contents - They contain all the user needs for interpretation and further processing of the data, including relevant product quality information (see next sections for more details) | 4 |
| MDR-2-SM-50KM | Only used in Level 2 25-km grid spacing products | 5 |
|
| VIADR-VER | Processor and auxiliary file versions used | Not relevant for end-user | 6 |
| VEADR-SMC | Name of input auxiliary file containing backscatter correction factors | Not relevant for end-user | 7 |
| VEADR-CURV | Soil Moisture parameter database | Not relevant for end-user | 8 |
| VEADR-CURV-NOISE | Soil Moisture parameter database | Not relevant for end-user | 9 |
| VEADR-DRY | Soil Moisture parameter database | Not relevant for end-user | 10 |
| VEADR-DRY-NOISE | Soil Moisture parameter database | Not relevant for end-user | 11 |
| VEADR-MS-MEAN | Soil Moisture parameter database | Not relevant for end-user | 12 |
| VEADR-NONSCAT | Soil Moisture parameter database | Not relevant for end-user | 13 |
| VEADR-SLOP | Soil Moisture parameter database | Not relevant for end-user | 14 |
| VEADR-SLOP-NOISE | Soil Moisture parameter database | Not relevant for end-user | 15 |
| VEADR-WET | Soil Moisture parameter database | Not relevant for end-user | 16 |
| VEADR-WET-NOISE | Soil Moisture parameter database | Not relevant for end-user | 17 |
Table 6.11: Record types in ASCAT Level 2 Soil Moisture product
Occurrence information is summarised in the following table:
| Record | Occurrence |
| MPHR | Once per product |
| IPRs | Once each per product |
| MDR-2-SM-50KM, -25KM | Once per every line of nodes |
| VIADR-VER | Occurs at least once. Re-occurs each time the applicability of the information changes within the product. |
| VEADR-SMC | Occurs at least once. Re-occurs each time the applicability of the information changes within the product. |
| VEADR-CURV | As for VEADR-SMC |
| VEADR-CURV-NOISE | As for VEADR-SMC |
| VEADR-DRY | As for VEADR-SMC |
| VEADR-DRY-NOISE | As for VEADR-SMC |
| VEADR-MS-MEAN | As for VEADR-SMC |
| VEADR-NONSCAT | As for VEADR-SMC |
| VEADR-SLOP | As for VEADR-SMC |
| VEADR-SLOP-NOISE | As for VEADR-SMC |
| VEADR-WET | As for VEADR-SMC |
| VEADR-WET-NOISE | As for VEADR-SMC |
Table 6.12: Occurrence of records in ASCAT Level 2 Soil Moisture product
See Section 12 for more details on the contents and format of the ASCAT Level 2 Soil Moisture product.
The contents and formats of the individual fields of the ASCAT HDF5 products are the same as for the EPS native format. The organisation of the data is different. Typically, the EPS native format presents each line of nodes and corresponding parameters as one complete sequence, which is successively repeated until the whole swath is completed. In conversion to HDF5 the measurement values and associated parameters are grouped into separate arrays.
Detailed format descriptions are provided in [RD19]. The products retrieved from the EUMETSAT Data Centre have the same names as the original EPS formatted ones, with the extension appended: ‘.h5’ for HDF5 formatted products, ‘.nat’ for products in the native EPS format. The products can be read using standard HDF libraries. For more information on HDF5 formats in general, see the HDF5 webpages.
The ASCAT products available in WMO (BUFR) format are summarised in the table below.
| Product | Bulletin header | Originating station | Descriptor sequence |
| ASCAT Level 1b spatially averaged products - 25 km spacing grid | IESXii (ii from 01 to 10) |
EUMP |
3-12-061 |
| ASCAT Level 1b spatially averaged products - 12.5 km spacing grid | IESXii (ii from 11 to 99) | ||
| ASCAT Level 2 soil moisture products - 25 km spacing grid | IEOXii (ii from 01 to 10) | ||
| ASCAT Level 2 soil moisture products - 12.5 km spacing grid | IEOXii (ii from 11 to 99) | ||
| ASCAT Level 2 multi-parameter products global - 25 km spacing grid | ISXXii (ii from 01 to 06) |
EHDB |
|
| ASCAT Level 2 wind products regional - 25 km spacing grid | ISXNii (ii from 01 to 06) | ||
| ASCAT Level 2 wind products - 12.5 km spacing grid | ISXNii (ii from 11 to 16) |
Table 6.13: ASCAT products available in WMO (BUFR) format
Note that there is a single BUFR format to incorporate the ASCAT L1b spatially averaged products and the L2 Soil Moisture and Near Surface Winds. If any of the product levels are not present, the corresponding fields are set to missing values. The full format description of these products is available in the WMO Manual on Codes [RD46]. Further information on the ASCAT Level 2 products is available in [RD31] and [RD32].
In order to distinguish between BUFR products from the global or the EARS processing chain, the descriptor Originating Sub-centre (001034) is set to 1 for the latter.
The names of the ASCAT Level 1b and Level 2 BUFR products distributed on EUMETCast are specified in [RD21]. They follow the pattern:
- ascat_yyyymmdd_hhmmss_metopa_nnnnn_eps_o_iii_xxx.lj_bufr (for the global products)
- ascat_yyyymmdd_hhmmss_metopa_nnnnn_ear_o_iii.lj_bufr (for the regional products)
where:
yyyymmdd stands for the UTC year, month, day of the data start sensing time hhmmss stands for the UTC hour, minute, second of the data start sensing time nnnnn is the orbit number j is ‘1’ or ‘2’ reflecting the product level iii can take the value:
- '250'/'125' for the L1b 25/12.5 km grid spacing product
- '250_ovw'/'125_ovw' for the L2 winds 25/12.5 km grid spacing product
- '250_ssm'/'125_ssm' for the L2 soil moisture 25/12.5 km grid spacing product_xxx is an optional string to denote parameter (e.g. _ssm for soil moisture)
Ocean surface winds generated by the OSI SAF are provided additionally in NetCDF format, the structure and contents of the files having been defined following the Climate and Forecast (CF) metadata conventions for the description of Earth sciences data.
A description of the contents of the ASCAT winds NetCDF data is provided via the OSI SAF scatterometer webpage.