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With this cycle upgrade, the medium-range ensemble and its monthly extension see a major upgrade in the dynamical ocean model (NEMO): the resolution is increased from 1 degree and 42 layers to 0.25 degrees and 75 layers (ORCA025Z75). Furthermore, NEMO model version v3.4.1 with the interactive sea-ice model (LIM2) is implemented. The ocean and sea-ice components of the ENS initial conditions are provided by the new ocean analysis and reanalysis suite ORAS5, which uses the new ocean model and revised ensemble perturbation method.
The page will be updated as required. It was last changed on 1921.09.2016. The next expected update to this page will be on 10.10.2016.
For a record of changes made to this page please refer to Document versions.
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Timetable for implementation
The planned timetable for the implementation of IFS cycle 43r1 is as follows:
| Date | Event |
|---|---|
| 22 Sep 2016 | Initial announcement to Member States |
| Week beginning 17 Oct 2016 | Availability of test data in dissemination |
| 22 Nov 2016 | Expected date of implementation |
The timetable represents current expectations and may change in light of actual progress made.
Meteorological content of the new cycle
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Technical details of the new cycle
Upgrade to the dynamical ocean model
The medium-range ensemble and its monthly extension see a major upgrade in the dynamical ocean model. The main changes are summarised in the table.
| Old | New | |
|---|---|---|
| Ocean model version | NEMO v3.4.1 | NEMO v3.4.1 |
| Configuration | ORCA1Z42 | ORCA025Z75 |
Horizontal resolution | 1.0° | 0.25° |
| Vertical layers | 42 | 75 |
| Time step | 3600s | 1200s |
| Initial conditions | ORAS4 using NEMO v3.0 | ORAS5 using NEMO v3.4.1 |
| Sea-ice coupling | None | LIM2 |
ORAS5 complements the current ocean reanalysis system (ORAS4) until there is no longer need for the ORAS4 output.
Changes to GRIB encoding
Model identifiers
The GRIB model identifiers (generating process identification number) for the new cycle will be changed as follows:
| GRIB 1 Section 1 Octets | GRIB 2 Section 4 Octets | grib_api key | Component | Model ID | |
|---|---|---|---|---|---|
| Old | New | ||||
| 6 | 14 | generatingProcessIdentifier | Atmospheric model | 146 | 147 |
| Ocean wave model | 111 | 112 | |||
| HRES stand-alone ocean wave model | 211 | TBC | |||
Software
EMOSLIB
EMOSLIB 433 is needed to interpolate successfully the wave energy flux mean direction (wefxd) parameter introduced at IFS cy43r1.
GRIB API
GRIB API version 1.17.0 provides full support for the new model output parameters introduced in IFS Cycle 43r1.
Older versions of GRIB API can decode the IFS Cycle 43r1 products successfully but users are advised to use at least GRIB API version 1.14.5, which provides full support for the octahedral reduced Gaussian grid.
Availability of test data from the IFS Cycle 43r1 pre-operational e-suite
Test data in MARS
Test data from the IFS Cycle 43r1 e-suite are available in MARS. The data are available with experiment version 0070 (MARS keyword EXPVER=0070) starting from 06 UTC on 10 August 2016.
The data can be accessed in MARS from:
Only registered users of ECMWF computing systems will be able to access the test data sets in MARS.
The data are intended for testing technical aspects only and should not be used for operational forecasting. Please report any problems you find with this data to User Support.
Test data in dissemination
Availability of test data in dissemination is expected to be announced during the week beginning 17 October 2016.
Document versions
| Date | Reason for update |
|---|---|
| 19.09.2016 | Initial version |
| 22.09.2016 | Initial announcement to Member States |