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The page will be updated as required. It was last changed on 0420.10.2017
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
16.10.2017: The long range forecast documentation page has been updated, to include the SEAS5 user guide.
16.10.2017: Pre-operational SEAS5 charts are available under https://www.ecmwf.int/en/forecasts/charts/seasonal_system5/
11.10.2017: We now have modified the operational dissemination requirements to request SEAS5 data. Users can update their operational requirements, as needed. Any change made will be used for the first time in the SEAS5 run of November. Changes to the dissemination requirements for System 4 are no longer possible.
04.10.4/10/2017: The re-archiving of the problematic SEAS5 pressure level derived fields has completed last night and we have validated the data this morning.
3/03.10/.2017: We have identified a problem with some archived pressure level fields for some derived fields associated with the real-time forecasts. The fields affected are type=hcmean from stream msmm, and types fcmean and em from stream mmsa. Pressure level fields from 925 hPa up to 1 hPa are affected, for dates from January to September 2017. Surface fields and 1000hPa pressure level fields are not affected.
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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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SEAS5 test data are now available in dissemination for the run of August 2017 onwards. SEAS5 test dissemination files are queued into ECPDS in delayed (standby) mode. Users can trigger the transmission of wanted test products at their convenience by logging into the test ECPDS system at https://ecpds-xmonitor.ecmwf.int/ in the usual manner. Users can find the SEAS5 by selecting all the datesin dates in the interface. In order to receive the test products, users will have to open their firewall to the relevant ECPDS Data Movers:
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At the moment, SEAS5 test data are generated based on the current (SYSTEM=4) dissemination requirements. Users wishing to test new SEAS5 products or to request fields at a higher resolution can change their requirements at https://ecaccess.ecmwf.int:7443/do/product/requirements. Note that the SEAS5 requirements now include the directive 'SYSTEM=5'. Any changes made will be effective with the next run of SEAS5 dissemination requirements.
SEAS5 T319/O320 products can be requested in their original representation as well as in the previously supported representations in System 4. Supported latitude/longitude resolutions in the System 5 are:
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| Note |
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| On the day of SEAS5 implementation into ECMWF operations, currently expected due for 5 November 2017, no test requirements will be carried into the operational mainframe. Users wishing to make their modified test SEAS5 requirements operational on the implementation date can make these changes in the operational ECPDS system (https://ecaccess.ecmwf.int:9443/do/product/requirements) or will have to let ECMWF (Data Services) know two weeks prior to the announced implementation date. |
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SEAS5 has run for May, June, July 2017 in beta testing (experiment=9001). SEAS5 will run in near real-time from September onwards. SEAS5 data will then become available shortly after the System 4 data have been released.
On the switch-over date, presently expected to be for the November rundue for 5 November, SEAS5 will become the operational system. The SEAS5 dissemination file names will then end with EXPVER '1'. System 4 will continue to be run as a near real-time system, for a limited period of time. Data from System 4 will be available from MARS and, for those interested, through dissemination on request. Those interested should in delayed mode, on request. Those interested can transfer the System 4 files through the test ECPDs system (https://ecpds-xmonitor.ecmwf.int/) or lshould contact Data Services at ECMWF. On the implementation date of SEAS5, users who requested to keep getting System 4 data though dissemination will receive both the SEAS5 and System 4 files via ECPDS, with the System4 file names including EXPVER '9004', e.g. ALL1101000010______9004.
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Graphical products from the seasonal forecast system are displayed on the Forecast Charts pages of the ECMWF website. We will make the SEAS5 graphical products available on the ECMWF website as soon as possiblePre-operational SEAS5 charts for Jan-Oct 2017 are available at https://www.ecmwf.int/en/forecasts/charts/seasonal_system5/.
Time-critical applications
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 |
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| 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. |
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| 2017 |
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