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News
- The expected date for the operational implementation of IFS cycle 46r1 is . We will confirm this date early in May.
- The second set of live-streamed seminars for cycle 46r1 will take place on at 09:30 BST and on at 17:00 BST.
- The IFS Cycle 46r1 test data is available in MARS including new model output parameters.
Cycle 46r1 live-streamed seminars
We will organise two live-streamed seminars to introduce the new IFS cycle 46r1. The first seminar has mainly covered the Scientific changes made in the new Cycle (see recording and slides below). The second seminar will focus more on the meteorological impact and scores of the new cycle, with details on how to access the Cycle 46r1 release candidate test data. This second seminar will take place on Wednesday, at 09:30 BST and repeated on Thursday, at 17 :00 BST. You will have the opportunity to raise any questions during all these seminars. Please do not hesitate to contact us for additional questions.
To attend any of these seminars, please follow the link below:
https://ecmwf.adobeconnect.com/ecmwf-46r1
There is no need to pre-register.
The recording of the first cycle 46r1 seminar is available at https://ecmwf.adobeconnect.com/pgy081jw03ya/. The presentation slides are also available separately at https://www.ecmwf.int/sites/default/files/medialibrary/2019-02/46r1_overview_AndyBrown.pdf.
Timetable for implementation
The planned timetable for the implementation of the cycle 46r1 is as follows:
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Expected date of implementation
The timetable represents current expectations and may change in light of actual progress made.
Meteorological content of the new cycle
Assimilation
- Continuous data assimilation. Number of 4D-Var outer loops increased from 3 to 4. Early delivery assimilation window length increased from 6 to 8 hours. Observation cut off time extended.
- Ensemble of Data Assimilations (EDA) increased from 25 members to 50 members.
- Use of the EDA spread to compute the Simplified Extended Kalman Filter (SEKF) soil analysis Jacobians.
- Weakly coupled data assimilation introduced for sea-surface temperature in the tropics only.
- Consistent spatial interpolation of the model to observation locations in trajectories and minimisations. Interpolation in nonlinear trajectories changed from bicubic to bilinear interpolation.
- RTTOV upgraded from v12.1 to v12.2.
Observations
- Assimilation of SMOS neural network soil moisture product.
- Assimilation of SSMIS-F17 150h GHz and GMI 166 v/h GHz.
- Improved use of land sea mask in the field of view for microwave imagers.
- Introduction of interchannel observation error correlations for ATMS.
- Introduction of interchannel observation error correlations for geostationary water vapour channels.
- Slant path calculations for geostationary radiances.
- Extend usage of geostationary radiances to higher zenith angles.
- Consistent infrared aerosol detection
For further details, read Main Contributions in data assimilation and observations.
Model
- Improvements in convection scheme (entrainment, CAPE closure, shallow convection).
- Activate LW scattering in radiation scheme.
- 3D aerosol climatology replaces 2D climatology.
- Correct scaling of dry mass flux in diffusion scheme.
- Improvement of the TL/AD of the semi-Lagrangian departure point scheme in the polar cap area.
- Fix instability in 2m temperature diagnostic related to wet tile.
- Bug fix in the computation of rain amount that could freeze when intercepted by the snow-pack.
- New parametrisations for wind input and deep water dissipation for for the wave model.
- Limit on wave spectrum for very shallow water and minimum depth set to 3m.
- ENS makes use of 50 EDA-members and initial perturbations are made exchangeable.
- ENS radiation time-step is reduced from 3 hours to 1 hour, to be consistent with HRES.
For further details, read Main Contributions in modelling
Re-forecasts
The new IFS cycle 46r1 will use the ERA5 data to initialize the re-forecasts and also use ERA5 EDA to perturb the re-forecasts initial conditions.
Technical details of the new cycle
Changes to GRIB encoding
Model identifiers
The GRIB model identifiers (generating process identification number) for cycle 46r1 will be changed as follows:
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New model output parameters
Extended output have been added in cycle 46r1, including a subset of ocean fields on the atmospheric grid.
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Near-surface wind output
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Wave induced mean sea level correction
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HRES-WAM / HRES-SAW / ENS-WAM
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Sea-ice thickness
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HRES / ENS
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This parameter is the gravitational potential energy of a unit mass, at a particular location, relative to mean sea level.
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HRES / ENS *
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This parameter is the mass of ozone per kilogram of air.
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HRES / ENS *
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Potential Temperature
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HRES / ENS *
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Pressure
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HRES / ENS *
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This parameter is the mass of water vapour per kilogram of moist air.
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HRES / ENS *
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This parameter is the eastward component of the wind. It is the horizontal speed of air moving towards the east, in metres per second. A negative sign thus indicates air movement towards the west.
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HRES / ENS *
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This parameter is the northward component of the wind. It is the horizontal speed of air moving towards the north, in metres per second. A negative sign thus indicates air movement towards the south.
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HRES / ENS *
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* The perturbed forecasts for the ENS only contain the parameters pt, u and v.
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Total precipitation of at least 25 mm
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Total precipitation of at least 25 mm
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ENS
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Total precipitation of at least 50 mm
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Total precipitation of at least 50 mm
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ENS
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Total precipitation of at least 100 mm
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Total precipitation of at least 100 mm
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ENS
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10 metre wind gust of at least 10 m/s
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10 metre wind gust of at least 10 m/s
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ENS
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The speed of horizontal air movement in metres per second.
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The speed of horizontal air movement in metres per second.
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ENS
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This parameter is the temperature in the atmosphere.
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This parameter is the temperature in the atmosphere.
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ENS
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Water vapour flux index
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EFI and SOT for water vapour flux
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ENS
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Software
ecCodes
ecCodes version 2.12.0 provides full support for the new model output parameters introduced in IFS Cycle 46r1.
Availability of test data from the IFS cycle 46R1 test suites
Test data in MARS
Test data from the IFS Cycle 46r1 test suites are available in MARS. The data are available with experiment version 0073 (MARS keyword EXPVER=0073) starting from 00 UTC on 29 January 2019.
The data can be accessed in MARS from:
- HRES (class=od, stream=oper, expver=73)
- Wave HRES (class=od, stream=wave, expver=73)
- ENS (class=od, stream=enfo, expver=73)
- ENS Wave (class=od, stream=waef, expver=73)
Only registered users of ECMWF computing systems will be able to access the test data sets in MARS.
Warning |
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We recommend users to use the MARS keyword "PARAMETER=paramId", as the shorName or full name may be ambiguous. E.g. for the new Wave model output, use "PARAMETER=140098" and not "PARAMETER=weta" or "PARAMETER=Wave induced mean sea level correction". |
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 Service Desk.
Test data in dissemination
IFS Cycle 46r1 test data will become available through the test dissemination system when we will have reached the release candidate stage.
Further reading
Peter Lean, Massimo Bonavita, Elías Hólm, Niels Bormann,Tony McNally: "Continuous data assimilation for the IFS" - ECMWF Newsletter 158. Available at https://www.ecmwf.int/en/newsletter/158/meteorology/continuous-data-assimilation-ifs
Simon Lang, Elías Hólm, Massimo Bonavita, Yannick Trémolet (JCSDA, US): "A 50-member Ensemble of Data Assimilations" - ECMWF Newsletter 158. Available at https://www.ecmwf.int/en/newsletter/158/meteorology/50-member-ensemble-data-assimilations
- ECMWF 's website news item: "Upgrade to boost quality of ocean wave forecasts". Available at https://www.ecmwf.int/en/about/media-centre/news/2019/upgrade-boost-quality-ocean-wave-forecasts
- Frédéric Vitart, Gianpaolo Balsamo, Jean-Raymond Bidlot, Simon Lang, Ivan Tsonevsky, David Richardson, Magdalena Alonso-Balmaseda: "Use of ERA5 to Initialize Ensemble Re-forecasts" - ECMWF Technical Memorandum nr. 841. Available at https://www.ecmwf.int/en/elibrary/18872-use-era5-initialize-ensemble-re-forecasts
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- test data in MARS
- recording and presentation slides for fist seminar
- further reading
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