#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 livestreamed 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 livestreamed seminars
We will organise two livestreamed 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/ecmwf46r1
There is no need to preregister.
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/201902/46r1_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  Livestreamed seminar 1 
May 2019  Availability of test data in dissemination 
15 May and 16 May 2019  Livestreamed 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 4DVar 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 seasurface 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 SSMISF17 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 semiLagrangian 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 snowpack.
 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 EDAmembers and initial perturbations are made exchangeable.
 ENS radiation timestep is reduced from 3 hours to 1 hour, to be consistent with HRES.
For further details, read Main Contributions in modelling
Reforecasts
The new IFS cycle 46r1 will use the ERA5 data to initialize the reforecasts and also use ERA5 EDA to perturb the reforecasts 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  
HRESSAW ( 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 

Nearsurface 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  HRESWAM / HRESSAW / ENSWAM  TBC  TBC  
140099  wraf  Ratio of wave angular and frequency width  Ratio of wave angular and frequency width  dimensionless  1  HRESWAM / HRESSAW / ENSWAM  TBC  TBC  TBC  
140100  wnslc  Number of events in freak waves statistics  Number of events in freak waves statistics  dimensionless  1  HRESWAM / HRESSAW / ENSWAM  TBC  TBC  
140101  utaua  Ucomponent of atmospheric surface momentum flux  Ucomponent of atmospheric surface momentum flux  N m^{2}  1  HRESWAM / HRESSAW / ENSWAM  TBC  TBC  
140102  vtaua  Vcomponent of atmospheric surface momentum flux  Vcomponent of atmospheric surface momentum flux  N m^{2}  1  HRESWAM / HRESSAW / ENSWAM  TBC  TBC  
140103  utauo  Ucomponent of surface momentum flux into ocean  Ucomponent of surface momentum flux into ocean  N m^{2}  1  HRESWAM / HRESSAW / ENSWAM  TBC  TBC  
140104  vtauo  Vcomponent of surface momentum flux into ocean  Vcomponent of surface momentum flux into ocean  N m^{2}  1  HRESWAM / HRESSAW / ENSWAM  TBC  TBC  
140105  wphio  Wave turbulent energy flux into ocean  Wave turbulent energy flux into ocean  W m^{2}  1  HRESWAM / HRESSAW / ENSWAM  TBC  TBC  TBC  
Ocean parameters available at the surface, produced by the NEMO model.  
174098  sithick  Seaice thickness *  Seaice 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.  m^{2} 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  
131098  tpg25  Total precipitation of at least 25 mm  Total precipitation of at least 25 mm  dimensionless  2  ENS  TBC  TBC  
131099  tpg50  Total precipitation of at least 50 mm  Total precipitation of at least 50 mm  dimensionless  2  ENS  TBC  TBC  
131085  tpg100  Total precipitation of at least 100 mm  Total precipitation of at least 100 mm  dimensionless  2  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  2  ENS  TBC  TBC  
133093  ptsa_gt_1stdev  Probability of 850hPa 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 850hPa 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 850hPa 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 850hPa 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 850hPa 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  Probability of 850hPa 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 Tails (SOT)  
132045  wvfi  Water vapour flux index  EFI and SOT for water vapour flux  dimensionless  1  ENS  TBC  TBC  
132167  2ti  2 metre temperature index  EFI and SOT for weekly mean temperature  dimensionless  1  ENSEXTENDED  TBC  TBC  TBC  
132228  tpi  Total precipitation index  EFI and SOT for 1 week total precipitation  dimensionless  1  ENSEXTENDED  TBC  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/continuousdataassimilationifs
Simon Lang, Elías Hólm, Massimo Bonavita, Yannick Trémolet (JCSDA, US): "A 50member Ensemble of Data Assimilations"  ECMWF Newsletter 158. Available at https://www.ecmwf.int/en/newsletter/158/meteorology/50memberensembledataassimilations
 ECMWF 's website news item: "Upgrade to boost quality of ocean wave forecasts". Available at https://www.ecmwf.int/en/about/mediacentre/news/2019/upgradeboostqualityoceanwaveforecasts
 Frédéric Vitart, Gianpaolo Balsamo, JeanRaymond Bidlot, Simon Lang, Ivan Tsonevsky, David Richardson, Magdalena AlonsoBalmaseda: "Use of ERA5 to Initialize Ensemble Reforecasts"  ECMWF Technical Memorandum nr. 841. Available at https://www.ecmwf.int/en/elibrary/18872useera5initializeensemblereforecasts
Document versions
Date  Reason for update 

 Initial version 




2 Comments
Steffen Weber
The first seminar ... will take place on Tuesday, 26 Feb. 2019 at 09:30
Which time zone?
Dominique Lucas
UTC. Added this to the document. Thanks.