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The details of each forecasting system correspond to the values of the "system" keyword (as used both in the CDS API and on the CDS interactive download forms). A full description of the use of that keyword and its correspondence with the different forecast systems names is available from the "Description of the C3S seasonal multi-system" page.
| Nominal Start Dates | C3S multi-system operational components ('system' keyword values) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| ECMWF | Météo-France | UK MetOffice | DWD | CMCC | NCEP | JMA | ECCC | BOM | |
| August 2025 - present | 51 | 9 | 604 | 22 | 4 | 2 | 3 | 4 and 5 | 2 |
| May 2025 - July 2025 | 51 | 9 | 604 | 22 | 35 | 2 | 3 | 4 and 5 | 2 |
| April 2025 | 51 | 8 | 604 | 22 | 35 | 2 | 3 | 4 and 5 | |
| March 2025 | 51 | 8 | 604 | 21 | 35 | 2 | 3 | 4 and 5 | |
| August 2024 - February 2025 | 51 | 8 | 603 | 21 | 35 | 2 | 3 | 4 and 5 | |
| July 2024 | 51 | 8 | 603 | 35 | 2 | 3 |
| ||
| March 2024 - June 2024 | 51 | 8 | 603 | 21 | 35 | 2 | 3 | 2 and 3 | |
| March 2023(4) - February 2024 | 51 | 8 | 602 | 21 | 35 | 2 | 3 | 2 and 3 | |
| November 2022 - Februrary 2023 | 51 (3) | 8 | 601 | 21 | 35 | 2 | 3 | 2 and 3 | |
| March 2022 - October 2022 | 5 | 8 | 601 | 21 | 35 | 2 | 3 | 2 and 3 | |
| February 2022 | 5 | 8 | 600 | 21 | 35 | 2 | 3 | 2 and 3 | |
| December 2021 - January 2022 | 5 | 8 | 600 | 21 | 35 | 2 | 2 | 2 and 3 | |
| July 2021 - November 2021 | 5 | 8 | 600 | 21 | 35 | 2 | 2 | 1 and 2 | |
| May 2021 - June 2021 | 5 | 7 | 600 | 21 | 35 | 2 | 2 | 1 and 2 | |
| March 2021 - April 2021 | 5 | 7 | 600 | 21 | 35 | 2 | 2 | ||
| November 2020 - February 2021 | 5 | 7 | 15 | 21 | 35 | 2 | 2 | ||
| October 2020 | 5 | 7 | 15 | 2 | 35 | 2 | 2 | ||
| May 2020 - September 2020 | 5 | 7 | 15 | 2 | 3 | 2 | |||
| October 2019 - April 2020 | 5 | 7 | 14 | 2 | 3 | 2 | |||
| May 2019 - September 2019 | 5 | 6 | 14 (2) | 2 | 3 | ||||
| November 2018 - April 2019 | 5 | 6 | 13 | 2 | 3 | ||||
| May 2018 - October 2018 | 5 | 5 | 13 | ||||||
| November 2017 - April 2018 | 5 | 5 | 12 (1) | ||||||
| September 2017 - October 2017 | 4 | 5 | 12 | ||||||
Legend:
| bold font | forecast systems introduced for the first time at the beginning of the nominal start dates range |
| non-bold font | forecast systems that were excluded from the multi-system at that time |
Notes:
(1) From February 2018: upgrade on data provision: changes in set of parameters available, see column noted with 'C3S-0.1 netcdf' in this link. Data deficiencies fixed, see known issues D2 and D3.
(2) Data deficiencies fixed, see known issue D9.
(3) Due to technical reasons, a new version of ECMWF SEAS5 data has been created using the keyword system=51.
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| Nominal start date (operational systems) | Météo-France | Met Office(a) | DWD | BOM | CMCC | Nominal start date (discontinued systems) | ECMWF | Met Office (a) | ECCC | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| System 9 (system=9) | GloSea6 (system=604) | GCFS2.2 (system=22) | ACCESS-S2 (system=2) | SPS4 | System 4 (system=4) | GloSea5-GC2-LI (system=15) | GEM-NEMO (system=1) | ||||||
| January |  | | | | | January | |  (c) | | ||||
| February | | | | | | February | | | | ||||
| March | | | | | | March | | | | ||||
| April | | | | | | April | | | | ||||
| May | | | | | * | May | | | | ||||
| June | | | | | | June | | | | ||||
| July | | | | | | July | | | | ||||
| August | | | | | * | August | | | | ||||
| September | | | | | * | * | * | * | * | September | | | |
| October | | | | | | October | | | | ||||
| November | | | | | | November | | | | ||||
| December | | | | | | December | | | |
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Complete set of start dates
| Origin | Forecast systems |
|---|---|
| ECMWF | SEAS5 (system=5) |
| Météo-France | System5 (system=5) System6 (system=6) System7 (system=7) System8 (system=8) |
| UK Met Office(a)(c) | GloSea5-GC2 (system=12,13) GloSea5-GC2-LI (system=14) GloSea6 (system=600,601,602,603) |
| DWD | GCFS2.0 (system=2) GCFS2.1 (system=21) |
| CMCC | SPSv3 (system=3) SPSv3.5 (system=35) |
| NCEP | CFSv2 (system=2) |
| JMA | CPS2 (system=2) |
| ECCC | CanCM4i (system=2) |
(a)For the Met Office contribution, due to the production of hindcasts "on-the-fly", the CDS keyword 'system' does not have the same meaning as for the other contributors. More details here.
(b) Due to technical reasons, a new version of ECMWF SEAS5 data has been created using the keyword system=51. See details on Announcements (date 12/October/2022)
(c) Hindcast data for January 1993 is not available from MetOffice forecast systems (see "known issue" G4 on the data gaps section)
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