#newfcsystem
Description of upgrade
IFS Cycle 46r1 is an upgrade with many scientific contributions, including changes in data assimilation (both in the EDA and the 4DVAR), in the use of observations, and in modelling. The new cycle only includes meteorological changes; there are no technical changes, e.g. new resolutions.
The page will be updated as required. It was last changed on 05.04.2018
For a record of changes made to this page please refer to Document versions.
Further information and advice regarding the upgrade can be obtained from User Support.
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:
| Date | Event |
|---|---|
| January 2019 | Initial announcement |
| 26 February and 07 March 2019 | Live-streamed seminar 1 |
| May 2019 | Availability of test data in dissemination |
| 15 May and 16 May 2019 | Live-streamed seminar 2 |
| 11 June 2019 | 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:
| GRIB 1 Section 1 Octets | GRIB 2 Section 4 Octets | eccodes key | Component | Model ID | |
|---|---|---|---|---|---|
| Old | New | ||||
| 6 | 14 | generatingProcessIdentifier | Atmospheric model | 149 | 150 |
| Ocean wave model | 114 | 115 | |||
| HRES-SAW ( HRES stand alone ocean wave model) | 214 | 215 | |||
New model output parameters
Extended output have been added in cycle 46r1, including a subset of ocean fields on the atmospheric grid.
| paramId | shortName | name | Description | units | GRIB edition | Components | Test data available | Dissemination | ecCharts | Added to the Catalogue |
|---|---|---|---|---|---|---|---|---|---|---|
Near-surface wind output | ||||||||||
| 228239 | 200u | 200 metre U wind component | eastward component of the 200m wind. | m s-1 | 1 | HRES / ENS |  | TBC | TBC | |
| 228240 | 200v | 200 metre V wind component | northward component of the 200m wind. | m s-1 | 1 | HRES / ENS | | TBC | TBC | |
| Wave model parameters | ||||||||||
| 140098 | weta | Wave induced mean sea level correction | Wave induced mean sea level correction | m | 1 | HRES-WAM / HRES-SAW / ENS-WAM | | TBC | TBC | |
| 140099 | wraf | Ratio of wave angular and frequency width | Ratio of wave angular and frequency width | dimensionless | 1 | HRES-WAM / HRES-SAW / ENS-WAM | | TBC | TBC | TBC |
| 140100 | wnslc | Number of events in freak waves statistics | Number of events in freak waves statistics | dimensionless | 1 | HRES-WAM / HRES-SAW / ENS-WAM | | TBC | TBC | |
| 140101 | utaua | U-component of atmospheric surface momentum flux | U-component of atmospheric surface momentum flux | N m-2 | 1 | HRES-WAM / HRES-SAW / ENS-WAM | | TBC | TBC | |
| 140102 | vtaua | V-component of atmospheric surface momentum flux | V-component of atmospheric surface momentum flux | N m-2 | 1 | HRES-WAM / HRES-SAW / ENS-WAM | | TBC | TBC | |
| 140103 | utauo | U-component of surface momentum flux into ocean | U-component of surface momentum flux into ocean | N m-2 | 1 | HRES-WAM / HRES-SAW / ENS-WAM | | TBC | TBC | |
| 140104 | vtauo | V-component of surface momentum flux into ocean | V-component of surface momentum flux into ocean | N m-2 | 1 | HRES-WAM / HRES-SAW / ENS-WAM | | TBC | TBC | |
| 140105 | wphio | Wave turbulent energy flux into ocean | Wave turbulent energy flux into ocean | W m-2 | 1 | HRES-WAM / HRES-SAW / ENS-WAM | | TBC | TBC | TBC |
| Ocean parameters available at the surface, produced by the NEMO model. | ||||||||||
| 174098 | sithick | Sea-ice thickness * | Sea-ice thickness | m | 1 | HRES / ENS | | TBC | TBC | |
| 151148 | mld | Mixed layer depth * | Mixed layer depth | m | 1 | HRES / ENS | | |||
| 151145 | zos | Sea surface height * | Sea surface height | m | 1 | HRES / ENS | | |||
| 151163 | t20d | Depth of 20C isotherm * | Depth of 20C isotherm | m | 1 | HRES / ENS | | |||
| 151130 | so | Sea water practical salinity * | Sea water practical salinity | psu | 1 | HRES / ENS | | |||
| 151164 | tav300 | Average potential temperature in the upper 300m * | Average potential temperature in the upper 300m | degrees C | 1 | HRES / ENS | | |||
| 151175 | sav300 | Average salinity in the upper 300m * | Average salinity in the upper 300m | psu | 1 | HRES / ENS | | |||
| * All fields are masked on land and lake points. tav300 and sav300 are masked on ocean points with depth < 300m. | ||||||||||
| Parameters on Potential Vorticity levels (1.5 and 2 PVU) | ||||||||||
| 129 | z | Geopotential | This parameter is the gravitational potential energy of a unit mass, at a particular location, relative to mean sea level. | m2 s-2 | 1 | HRES / ENS * | | TBC | TBC | |
| 203 | o3 | Ozone mass mixing ratio | This parameter is the mass of ozone per kilogram of air. | kg kg-1 | 1 | HRES / ENS * | | TBC | TBC | |
| 3 | pt | Potential Temperature | Potential Temperature | K | 1 | HRES / ENS * | | TBC | TBC | |
| 54 | pres | Pressure | Pressure | Pa | 1 | HRES / ENS * | | TBC | TBC | |
| 133 | q | Specific humidity | This parameter is the mass of water vapour per kilogram of moist air. | kg kg-1 | 1 | HRES / ENS * | | TBC | TBC | |
| 131 | u | U component of wind | 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. | m s-1 | 1 | HRES / ENS * | | TBC | TBC | |
| 132 | v | V component of wind | 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. | m s-1 | 1 | HRES / ENS * | | TBC | TBC | |
* The perturbed forecasts for the ENS only contain the parameters pt, u and v. | ||||||||||
| Ensemble probabilities | ||||||||||
| 131020 | talm2 | Temperature anomaly less than -2 K | Temperature anomaly less than -2 K | dimensionless | 1 | ENS | | TBC | TBC | |
| 131021 | tag2 | Temperature anomaly of at least +2 K | Temperature anomaly of at least +2 K | dimensionless | 1 | ENS | | TBC | TBC | |
| 131098 | tpg25 | Total precipitation of at least 25 mm | Total precipitation of at least 25 mm | dimensionless | 1 | ENS | | TBC | TBC | |
| 131099 | tpg50 | Total precipitation of at least 50 mm | Total precipitation of at least 50 mm | dimensionless | 1 | ENS | | TBC | TBC | |
| 131085 | tpg100 | Total precipitation of at least 100 mm | Total precipitation of at least 100 mm | dimensionless | 1 | ENS | | TBC | TBC | |
| 131100 | 10fgg10 | 10 metre wind gust of at least 10 m/s | 10 metre wind gust of at least 10 m/s | dimensionless | 1 | ENS | | TBC | TBC | |
| 133093 | ptsa_gt_1stdev | Probability of temperature standardized anomaly greater than 1 standard deviation | Probability of temperature anomaly greater than 1 standard deviation of the climatology. | dimensionless | 2 | ENS |  | |||
| 133094 | ptsa_gt_1p5stdev | Probability of temperature standardized anomaly greater than 1.5 standard deviation | Probability of temperature anomaly greater than 1.5 standard deviation of the climatology. | dimensionless | 2 | ENS | | |||
| 133095 | ptsa_gt_2stdev | Probability of temperature standardized anomaly greater than 2 standard deviation | Probability of temperature anomaly greater than 2 standard deviation of the climatology. | dimensionless | 2 | ENS | | |||
| 133096 | ptsa_lt_1stdev | Probability of temperature standardized anomaly less than -1 standard deviation | Probability of temperature anomaly less than -1 standard deviation of the climatology. | dimensionless | 2 | ENS | | |||
| 133097 | ptsa_lt_1p5stdev | Probability of temperature standardized anomaly less than -1.5 standard deviation | Probability of temperature anomaly less than -1.5 standard deviation of the climatology. | dimensionless | 2 | ENS | | |||
| 133098 | ptsa_lt_2stdev | of temperature standardized anomaly less than -2 standard deviation | Probability of temperature anomaly less than -2 standard deviation of the climatology. | dimensionless | 2 | ENS | | |||
| Ensemble mean / Ensemble standard deviation | ||||||||||
| 10 | ws * | The speed of horizontal air movement in metres per second. | The speed of horizontal air movement in metres per second. | m s-1 | 1 | ENS | | TBC | TBC | |
| 130 | t * | This parameter is the temperature in the atmosphere. | This parameter is the temperature in the atmosphere. | K | 1 | ENS | | TBC | TBC | |
| * These parameters have been added at 250 hPa. | ||||||||||
| Extreme Forecast Index (EFI) - Shift Of Tail (SOT) | ||||||||||
| 132045 | wvfi | Water vapour flux index | Water vapour flux index | dimensionless | 1 | ENS | | TBC | TBC | |
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.
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
Document versions
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| Initial version |
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