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News
- The IFS cycle 46r1 scorecards are now available.
- We have now reached the release candidate phase of the implementation of the new IFS Cycle 46r1.
- IFS cycle 46r1 test data is available in dissemination.
- Changes in some Cycle 46r1 data are highlighted.
- 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.
Meteorological impact of the new cycle
The following evaluation of the new cycle is based on the alpha and beta testing of the new Cycle. Scorecards for the new IFS Cycle 46r1 are now available.
Weather parameters and waves
The IFS Cycle 46r1 brings substantial improvements in forecast skill both for the ENS and the HRES. Medium-range forecast errors in the extra-tropics are reduced by 1-5% for upper-air and by 0.5-2% for surface parameters. Improvements of this magnitude are seen both against analysis and against observations. In terms of lead time, upper-air improvements amount to a gain of the order of 2-3 hours. In the tropics, HRES results are predominantly positive, but there are some increases in temperature and humidity errors, mainly seen in verification against analysis. For temperature, they are due to changes in the analysis and the introduction of a 3D aerosol climatology. ENS results in the tropics are also mixed, in addition to the already mentioned changes they are affected by a minor reduction in spread on the order of 1% due to changes in the deep convection scheme. Wave parameters (significant wave height and mean wave period) in the HRES are improved by 5-10% due to a major upgrade in the ocean wave model. Increased wave activity leads to some degradation in wave height at longer lead times in the ENS.
Precipitation forecast skill increases in the extra-tropics by about 0.5% in the ENS and 1% in the HRES. Other weather parameters, such as 2m temperature and 2m dewpoint, 10m wind speed, and total cloud cover improve by about 1% in the ENS, and by 0.5-1% in the HRES when verified against observations. In the tropics, slightly reduced spread and increased bias lead to a very small (0.1-0.2%) degradation in ENS precipitation. Scores in the tropics show strong improvements for 2m temperature (4-8% against analyses both in ENS and HRES), (1-2% against obs in ENS).
Tropical cyclones
Results for TCs are generally neutral. There is a slight improvement in the tracks consistent with improvements in tropical winds, but this signal has only marginal statistical significance.
Extended range
The extended-range impact of model changes associated with 46r1 is neutral, except for a small degradation of 2-metre temperature and precipitation skill scores in the tropics. However, the use of ERA5 instead of ERA-Interim as initial condition gives significant improvements in weeks 1-2 in the extratropics, and up to week 4 in the tropics.
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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Sea Surface Temperature
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With the new IFS cycle 46r1, the ecCodes key "localDefinitionNumber" for the Sea Surface Temperature (SST) analyses at 00Z and 12Z will be changed from 17 to 1, both in dissemination and in MARS. With this change, all SST and Sea Ice fields for the analyses and Forecasts will be harmonised. |
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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Changes in Cycle 46r1 data
EFI/SOT in the extended-range
With Cycle 46r1, the EFI and SOT become available in the extended-range forecast for two parameters: 7-day mean of 2m temperature and 7-day total precipitation. In contrast to the medium range, the model climate is derived from a set of 3 (rather than 9) re-forecast run dates, centred on the date of the real-time forecast initialisation (all are from 00UTC). The climate sample size is therefore much smaller and comprises 660 values compared to 1980 used in the medium range, but this does make the EFI and SOT consistent with other climate-related products from the extended-range forecasts, such as anomalies and probabilities.
New climatology for 850hPa Temperature anomaly probabilities
The outdated fixed climatology for computing historical 850hPa temperature anomaly probability parameters 131020 (talm2), 131021 (tag2), 131022 (talm8), 131023 (talm4), 131024 (tag4) and 131025 (tag8) is replaced by a new re-forecast-based climatology. The same climatology is also used to compute the Cycle 46r1 new (standard-deviation-related) 850hPa temperature anomaly probability parameters listed above. The new climatology is much more compatible with the real-time forecast.
A change to the computation of maximum CAPE and maximum CAPE-shear parameters
The two parameters 228035 (mxcape6) and 228036 (mxcapes6) namely “maximum CAPE in the last 6 hours” and “maximum CAPE-shear in the last 6 hours” respectively implemented with cycle 45r1, were computed in a complex way by combining hourly output of the model’s instantaneous CAPE (paramID=59) and CAPE-shear (paramID=228044) with a different type of CAPE, based on virtual temperature, that is used more directly by the model parametrisation where convection is active. This way of computing mxcape6 and mxcapes6 is inconsistent with the standard, instantaneous CAPE and CAPE-shear output fields provided by ECMWF hitherto. So to achieve more consistency, from cycle 46r1 we will change the mxcape6 and mxcapes6 variables to be based solely on the standard instantaneous hourly values of CAPE and CAPE-shear.
Software
ecCodes
ecCodes version 2.12.5 provides full support for the new model output parameters introduced in IFS Cycle 46r1.
Magics
Magics version 4.0.3 provides full support for the new model output parameters introduced in IFS Cycle 46r1.
Metview
Metview version 5.5.3 provides full support for the new model output parameters introduced in IFS Cycle 46r1.
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ECMWF will update its software packages to the above listed versions on |
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.
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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 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 from the release candidate testing stage are available through the test dissemination system, starting from the 12Z run on . Users of ECMWF dissemination products can trigger transmission of test products by logging in to the test ECPDS system at https://ecpds-xmonitor.ecmwf.int/ (or https://msaccess.ecmwf.int:7443) in the usual manner. In order to receive the test products, users have to have their firewall open to the relevant ECPDS Data Movers:
Internet transfers: 193.61.196.104 ( ecpds-xma.ecmwf.int ), 193.61.196.105 ( ecpds-xmb.ecmwf.int ) and 193.61.196.113 ( ecpds-xmc.ecmwf.int )
RMDCN transfers: 136.156.8.132 ( mspds-dm4.ecmwf.int ) and 136.156.8.133 ( mspds-dm5.ecmwf.int )
The IFS Cycle 46r1 test products are available as version number 73 (file names ending with '73'). The test products are generated shortly behind real-time and based on the operational dissemination requirements and the IFS Cycle 46r1 test data for HRES, HRES-WAM, HRES-SAW., ENS, ENS-WAM and ENS extended.
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The Cycle 46r1 new parameters listed above will become available in dissemination after the implementation of the cycle. |
Should you require any assistance with IFS Cycle 46r1 test dissemination products, please contact Data Services.
Graphical display of IFS cycle 46r1 test data
IFS cycle 46r1 graphical products will shortly become available.
Time-critical applications
Option 1 - simple time-critical jobs
Member State users of the "Simple time-critical jobs" framework can test that their scripts will work with the IFS Cycle 46r1 test data by using the limited ECaccess 'events' set up for this purpose:
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For these events, MSJ_EXPVER environment variable is set to 0073 and can be used to specify the IFS Cycle 46r1 test data in any MARS retrievals.
These events are intended for testing technical aspects only and should not be used for Time Critical activities.
Options 2 and 3
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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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- expected date for implementation announced
- announcement of dates for second live-streamed seminar.
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- Test data in dissemination
- Meteorological impact of the new cycle
- technical change to Sea Surface Temperature.
- Changes in Cycle 46r1 data.
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