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The page will be updated as required. It was last changed on 2008.1011.2017
For a record of changes made to this page please refer to Document versions.
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The planned timetable for the implementation of SEAS5 is as follows:
| Date | Event |
|---|---|
| 05 July 2017 | Initial announcement. Data available in MARS |
| 08 September 2017 | Availability of test data in dissemination |
| 05 November 2017 | Date of implementation |
The timetable represents current expectations and may change in light of actual progress made.
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We acknowledge the contribution of the Copernicus Climate Change Service (C3S) in the production of SEAS5. C3S provided the computer time for the generation of the re-forecasts for SEAS5 and for the production of the ocean reanalysis (ORAS5), used as initial conditions for the SEAS5 re-forecasts. SEAS5 will be the ECMWF contribution to the C3S multi-model seasonal forecast products, see paragraph 'SEAS5 and Copernicus services'.
Latest news
08.11.2017: We are pleased to confirm that the SEAS5 system was successfully implemented in operations on 5.11.2017. System 4 will keep running for a limited time.
16.10.2017: The long range forecast documentation page has been updated, to include the SEAS5 user guide.
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Note that the main monthly mean fields (stream=msmm, type=fcmean) are *not* affected. We will begin re-archiving the affected pressure level fields in MARS at 14:30UTC on the 3rd October, to correct the problem, and will confirm on this page when the re-archiving is complete. Please accept our apologies for any inconvenience caused.
Current Status
SEAS5 has now entered release candidate testing. The re-forecast data are fully available in MARS and Forecast data are also available in MARS and through dissemination. Graphical products will shortly be made available on our website
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SEAS5 was successfully implemented in operations on 5.11.2017.
New release day for SEAS5 data
We are pleased to announce that the SEAS5 products (data and charts) will be released 3 days earlier, on the 5th of each month at 12UTC. System 4 products are currently released on the 8th of each month.
Summary description of SEAS5
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The table below summarizes the upgrades in model components and initialization for SEAS5.
| System 4 | SEAS5 | |
|---|---|---|
| IFS Cycle | 36r4 | 43r1 |
| IFS horizontal resolution | TL255 | TCO319 |
| IFS Gaussian grid | N128 (80 km) | O320 (35 km) |
| IFS vertical resolution (TOA) | L91 (0.01 hPa) | L91 (0.01 hPa) |
| IFS model stochastic physics | 3-lev SPPT and SPBS | 3-lev SPPT and SPBS |
| Ocean model | NEMO v3.0 | NEMO v3.4 |
| Ocean horizontal resolution | ORCA 1.0 | ORCA 0.25 |
| Ocean vertical resolution | L42 | L75 |
| Sea ice model | Sampled climatology | LIM2 |
| Atmosphere initialization (Re-forecast/Forecast) | ERA-Interim/Operations | ERA-Interim/Operations |
Land Initialization | ERA-Interim land (36r4)/Operations | ERA-Interim land (43r1)/Operations |
| Ocean initialization | ORA-S4 | ORS-S5 |
| Forecast ensemble size | 51 (0-7m) 15 (8-13m) | 51 (0-7m) 15 (8-13m) |
| Re-forecast years | 30 (1981-2010) | 36 (1981-2016) |
| Re-forecast ensemble size | 15 (0-7m) 15 (8-13m) | 25 (0-7m) 15 (8-13m) |
| Calibration period | 1981-2010 | 1993-2016 |
| Products Release Date | The 8th of each month at 12UTC | The 5th of each month at 12UTC |
Meteorological content of SEAS5
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The GRIB model identifiers (generating process identification number) for SEAS5 will be changed as follows:
| GRIB 1 Section 1 Octets | GRIB 2 (only for SEAS5) Octets | grib_api/ecCodes key name | Component | Model ID | |
|---|---|---|---|---|---|
| System 4 | SEAS5 | ||||
| 6 | 14 (in Section 4) | generatingProcessIdentifier | Atmospheric model | 139 | 147 |
| Ocean wave model | 107 | 112
| |||
| 52-53 | 18-19 (in Section 2) | systemNumber | 4 | 5 | |
GRIB 2 data
SEAS5 model level data is coded in GRIB 2, compared to GRIB 1 for System 4. The change to GRIB 2 for model level data was introduced in IFS Cycle 37r2 in 2011. See under User impact below for more information.
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Several new parameters have been added related to the lake model, 6h instantaneous stresses have been added to help user applications such as wave modelling, and top incoming solar radiation has been added with a 24 hour output frequency. Note also that surface and sub-surface runoff are now fully available (in System 4, these parameters were available for the real-time forecasts, but only a limited number of the re-forecasts).
| paramId | name | frequency |
|---|---|---|
| 26 | Lake cover | Step 0 only |
| 228007 | Lake depth | Step 0 only |
| 228008 | Lake mixed layer temperature | 24 hour |
| 228014 | Lake ice depth | 24 hour |
| 229 | Instantaneous eastward turbulent surface stress | 6h |
| 230 | Instantaneous northward turbulent surface stress | 6h |
| 212 | Top incoming solar radiation | 24h |
| 8 | Surface runoff | 24h |
| 9 | Sub-surface runoff | 24h |
Surface fields output at additional timesteps
Some surface fields previously archived every 24 hours are now archived every 6 hours. As well as increased availability of synoptic data, this also changes the monthly means for the instantaneous fields such as SST and soil temperature. These are now calculated from 6 hourly data, and no longer have the diurnal cycle aliased into them. (For accumulated fields, the monthly mean rate of accumulation is independent of whether synoptic data is written at 6 or 24h intervals).
| paramId | name | frequency |
|---|---|---|
| 34 | Sea surface temperature | 6 hr |
| 144 | Snowfall | 6 hr |
| 139 | Soil temperature level 1 | 6 hr |
| 169 | Surface solar radiation downwards | 6 hr |
| 175 | Surface thermal radiation downwards | 6 hr |
| 228 | Total precipitation | 6 hr |
Model level data
SEAS5 model level data are now produced to 6 months instead of 5 months for System 4.
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All fields are output every 24 hours
| paramId | name |
|---|---|
| 140220 | Mean wave period based on the first moment |
| 140221 | Mean wave period based on the second moment |
| 140244 | Mean square slope of waves |
| 140249 | 10 m wind direction (no calculation of monthly mean/max/min/SD) |
Impact of SEAS5 on users
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Member State users of the "Simple time-critical jobs" framework can test that their scripts will work with the SEAS5 test data by using the new 'event' set up.
| Event ID | Event name | Description |
|---|---|---|
| 1763 | seasonal5_fc | At this stage, the system 5 Seasonal Forecast real time products have been updated. |
Users are reminded to change the directive 'SYSTEM=5' in their MARS requests.
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| Anchor | ||||
|---|---|---|---|---|
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| Date | Reason for update |
|---|---|
| 05.07.2017 |
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| 31.08.2017 |
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| 08.09.2017 |
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| 03.10.2017 |
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| 04.10.2017 |
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| 20.10.2017 |
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| 08.11.2017 |
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