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Description of the upgrade

A wide-ranging upgrade of ECMWF’s Integrated Forecasting System (IFS) 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. Cycle 45r1 brings better global weather forecasts, with particularly consistent gains in the extended range. A key plank of the upgrade is enhanced dynamic coupling between the ocean, sea ice and the atmosphere.


Implemented: 5 June 2018




  • We are happy to inform our users that the implementation of the new IFS cycle happened successfully. See News release.
  • We have been informed that five cycle 45r1 surface analysis fields (RSN, SST, SD, 2T and 2D) have generatingProcessIdentifier set to 148,  instead of 149. This will be corrected as of the run at 12UTC on 6 June 2018. We apologise for this oversight.
  • We would like to thank all our users for their feedback on IFS cycle 45r1. Please do contact our Service Desk for any other issue you may have with the new cycle 45r1 data and products.
titleSee older news ...


  • The issue with the Cycle 45r1 Simulated Satellite imagery data (see below) has been identified to a change in the units for water and ice content of the new RTTOV-12 data. We are please to inform you that this issue has been fixed as of the 12UTC run of 2 June 2018. This issue has not affected any other data than the Simulated Satellite imagery.


  • The parameter CI (sea-ice fraction, paramId 31) has wrongly been encoded using 24 bits per value, instead of 16, for the Analyses in the Cycle 45r1 test data: This issue only affects the data archived in MARS, not the data available through the dissemination. The problem has been fixed as of the Analysis of 18UTC on 31 May 2018.
  • We have identified an issue with the Cycle 45r1 Simulated Satellite imagery data. We are investigating this problem. These products may not be fixed in time for the implementation on 5 June. In this case, we will update the new Cycle 45r1 later to address this issue.

    Comparison of simulated satellite imagery between cycle 43r3 and cycle 45r1. (Click on image to see the comparison)
  • May we remind our users to download the  Cycle 45r1 expver 0072 re-forecasts from ECPDS, e.g for 4 June and 7 June, they need for their operational activities after the implementation of the new cycle.
  • The implementation of the new cycle is confirmed for Tuesday 5 June 2018. The first operational run using the new cycle will be the 06 UTC analysis and forecast in the Boundary Conditions Optional Programme on 5 June followed by the 12 UTC main assimilation and forecast. The monthly forecast extension to the ensemble will be run with the new IFS cycle for the first time the following Thursday 7 June 2018.


  • Please note that the bathymetry (water depth) has changed with the IFS Cycle 45r1 . See below for more information. Apologies for this late notification.
  • We have been informed about a change of values for the ecCodes key named timeRangeIndicator in the cycle 45r1 GRIB1 data at step 0 since the run of 18 April 2018 at 00Z. The cause of this change has been identified and is fixed for the 06Z BC run of 21 May 2018 onwards.
  • The CAMS (Copernicus Atmosphere Monitoring Service) real-time data assimilation and forecasting system will be upgraded to IFS cycle 45r1 on 26 June 2018. More information can be found in the Implementation of IFS cycle 45R1_CAMS.

Timeline of the implementation

The planned timetable for the implementation of the IFS Cycle 45r1 is as follows:




Initial Publication
April 2018Initial announcement, with test data in MARS
May 2018Availability of test data in dissemination
5 June 2018

Expected date of implementation

The timetable represents current expectations and may change in light of actual progress made.

Datasets affected

  • HRES
  • ENS


Unchanged from previous IFS cycle.


Horizontal resolution

Vertical resolution




~9 km




~18 km


ENS extended 


~36 km





~14 km




~28 km


ENS-WAM Extended


~55 km



NEMO 3.4


~28 km


Meteorological content


  • Weakly coupled sea-ice atmosphere assimilation applied with the use of OCEAN5 sea-ice (instead of OSTIA) in the surface analysis of the high-resolution (HRES 4d-Var) and the ensemble of data assimilations (EDA) analyses;
  • Relative humidity increments calculated using temperature instead of virtual temperature;
  • Weak constraint model error forcing applied at every time step instead of every hour to avoid shocks in the model integration.


  • Assimilation of non-surface-sensitive infra-red (IR) channels over land;
  • Assimilation of all sky micro-wave (MW) sounding channels over coasts;
  • Use of direct broadcast FY-3C MWHS2 data for better timeliness;
  • Introduction of RTTOV-12 and new microwave instrument coefficients;
  • Activation of constrained variational bias correction (VarBC);
  • Retuning of the radiosonde observation error, and introduction of a scheme to account for radiosonde drift;

  • Introduction of temperature bias correction of old-style AIREP observations; aircraft temperature varBC predictor upgraded to a three predictor model (cruise, ascent, descent); reduced thinning of aircraft data;

  • Assimilation of JASON-3 and Sentinel-3A altimeters, and use of new altimeters for wave data assimilation;


  • Coupling of the 3-dimensional ocean and atmosphere: introduction of the coupling to the NEMO 3-dimensional ocean model also in the high-resolution forecast (HRES), with the same ocean model version used in the medium-range/monthly ensemble (ENS): NEMO3.4 in ORCA025_Z75 configuration; upgrade of the NEMO-IFS coupling strategy in both ENS and HRES to a full-coupling in the tropical region (partial-coupling-extra-tropics);
  • Improved numerics for warm-rain cloud microphysics and vertical extrapolation for semi-lagrangian trajectory;
  • Increased methane oxidation rate to improve (increase) water vapour in the stratosphere;
  • Improved representation of super-cooled liquid water in convection, and minor convection updates;
  • Improvements in the tangent forward and adjoint models linked to the convection scheme;
  • Correction of soil thermal conductivity formulation and addition of soil ice dependency;
  • New extended output parameters have been added. See below.
  • Modified parameter for non-orographic gravity-wave drag scheme for 91 levels;
  • Model error changes:
    • Stochastically perturbed parametrization tendency scheme (SPPT): improved flow-dependent error representation via reduced spread in clear skies regions (due to unperturbed radiative-tendency in clear sky), activation of tendency perturbations in stratosphere, and weaker tapering of perturbations in boundary layer; amplitude reduction of the SPPT perturbations patterns (by 20%);
    • EDA: cycling of stochastic physics random fields in the EDA, and adoption of the same SPPT configuration in EDA as in ENS;
    • Stochastic kinetic energy backscatter scheme (SKEB): deactivation of the stochastic backscatter (SKEB) scheme due to improved model error representation by the SPPT scheme (see above), leading to a 2.5% cost saving in the ENS;

New bathymetry in wave models

With the IFS Cycle 45r1, we have upgraded the bathymetry (water depth) used in the wave models (HRES-WAM, HRES-SAW and ENS-WAM) based on ETOPO1.

The figures below show the new bathymetry used for HRES-WAM and ENS-WAM for Europe together with the difference with the previously used bathymetry (ETOPO2).


IFS cycle 45r1 bathymetry (ETOPO1)

Difference between IFS cycle 43r3 and 45r1 bathymetries


IFS cycle 45r1 bathymetry (ETOPO1)

Difference between IFS cycle 43r3 and 45r1 bathymetries

This change was in part driven by users pointing out that the previous bathymetry for the Baltic Sea was quite erroneous at few places. Change in water depth will mostly affect the wave fields in coastal area, generally resulting in higher wave heights where the water has become deeper and vice-versa.. Moreover, some WAM grid points have changed from sea to land (i.e. no waves at those points),  and vice versa. These locations are respectively shown in the right figures above , with green and black shadings (you may need to zoom into the pictures). This change of land/sea points will be visible for some coastal locations in the Wave ENSgrams and for users relying exclusively on the wave model values at those locations.

Meteorological impact and evaluation

The following evaluation of the new cycle is based on the alpha testing. 


The new cycle leads to improvements in HRES upper-air fields. Verified against the model analysis, a positive signal is seen throughout the troposphere for most parameters, except temperature in the lower troposphere at shorter ranges. The latter is mainly a result of changes to the analysis, as confirmed by corresponding neutral results against observations. Upper-air improvements are more pronounced in the tropics, especially for wind and temperature. Verified against observations, upper-air changes are overall positive in the tropics except for relative humidity, and neutral to slightly positive in the extratropics. Upper-air results for the ENS verified against analysis are mostly positive in the tropics but more neutral in the extratropics. The negative signal for temperature in the lower troposphere at shorter lead times is again mainly due to changes in the analysis. Against observations, results are mostly negative in the extratropics at early lead times and significantly positive in the tropics, with the exception of relative humidity at 700hPa. The negative impact in the extratropics is partly due to a slight reduction in ensemble spread associated with the transition to a physically more realistic SPPT scheme. Whether or not this reduced spread is genuinely detrimental depends on whether observation errors are taken into account in the verification which has not been done routinely so far. Experimental verification against radiosonde data that takes observation error into account indicates that a large fraction of the negative ENS results disappear or become statistically non-significant.

Weather parameters and waves

There is an overall improvement in 2m temperature both in the HRES and ENS, particularly for Europe. 2m humidity is largely neutral for HRES, but positive for ENS, particularly in the tropics. 10 m wind speed is largely neutral in the HRES and slightly negative in the ENS. Precipitation in the HRES is improved in terms of categorical verification (e.g. SEEPS), and near-coastal precipitation in warm-rain dominated situations is significantly improved due to changes in the cloud physics. However, these changes also lead to more activity at higher precipitation rates in active regions such as the East Asian monsoon, and as a result error measures such as RMSE or CRPS (for the ENS) are increased. The negative signal for significant wave height against analysis is a result of changes to the analysis from a large increase in observation usage, and verification against observations (buoys) shows the results are neutral for both HRES and ENS.

Tropical cyclones

The implementation of the ocean-atmosphere coupling in the HRES removes the overall negative bias in tropical cyclone central pressure and thereby reduces the mean absolute intensity error by about 10% in the short range, and about 20% from day 5 onwards. Evaluations so far show statistically neutral results for the position error.

Extended range

Changes in scores for the monthly system are generally positive across the range of parameters, with significance in week 1 for tropical winds. The only indication of a degradation is precipitation in the tropics with a consistent negative signal across all 4 weeks. There is an indication of a positive effect on skill across all parameters in the European domain. The MJO Index was significantly underspread, but changes in 45r1 to the SPPT scheme have brought the spread and error in close agreement throughout the 30 day forecast range. The underestimation of the MJO Index amplitude error has been significantly improved throughout the forecast.


Scorecards of the new cycle are now available.

New and changed parameters

New parameters

Extended output have been added in cycle 45r1, including precipitation rates, CAPE indices and a total lightning flash density.






GRIB edition


Test data available



Added to the Catalogue






GRIB edition


Test data available



Added to the Catalogue

228050litotiInstantaneous total lightning flash densityInstantaneous value of total (cloud-to-cloud and cloud-to-ground) lightning flash density. See also day-12


228051litota1Averaged total lightning flash density in the last hour
Averaged total (cloud-to-cloud and cloud-to-ground) lightning flash density in the last hour. See also day-12
HRES / ENS(tick)(tick)TBC(error)
228057litota3Averaged total lightning flash density in the last 3 hoursAveraged total (cloud-to-cloud and cloud-to-ground) lightning flash density in the last 3 hours. See also day-12
HRES / ENS(tick)(tick)TBC(tick)
228058litota6Averaged total lightning flash density in the last 6 hoursAveraged total (cloud-to-cloud and cloud-to-ground) lightning flash density in the last 6 hours. See also day-12
HRES / ENS(tick)(tick)TBC(tick)
260048tprateTotal precipitation rateTotal precipitation rate (instantaneous)kg m-2 s-12HRES / ENS(tick)(tick)TBC(tick)
228035mxcape6maximum CAPE in the last 6 hoursMaximum CAPE in the last 6 hours. See also here.J kg-12
HRES / ENS(tick)(tick)TBC(tick)
228036mxcapes6maximum CAPES in the last 6 hoursMaximum CAPE-shear in the last 6 hours. See also here.m2 s-22


162071viwveVertical integral of eastward water vapour fluxVertical integral of eastward water vapour flux. See also m-1 s-11HRES / ENS(tick)(tick)TBC(tick)
162072viwvnVertical integral of northward water vapour fluxVertical integral of northward water vapour flux. See also m-1 s-11HRES / ENS(tick)(tick)TBC(tick)
151131ocuEastward sea water velocityOcean current zonal componentm s-11HRES / ENS(tick)(tick)TBC(tick)
151132ocvNorthward sea water velocityOcean current meridional componentm s-11HRES / ENS(tick)(tick)TBC(tick)

For more details on the new lightning parameters, please read the Newsletter article "Promising results for lightning predictions".

Changes to existing parameters

Technical content

Changes to GRIB encoding

Model identifiers

The GRIB model identifiers (generating process identification number) for cycle 45r1 will be changed as follows:

Section 1
Section 4
grib_api key ComponentModel ID
6 14  generatingProcessIdentifierAtmospheric model148149
Ocean wave model113114
HRES stand-alone ocean wave model213214


We recommend the use of the following versions of ECMWF's software packages to manipulate the cycle 45r1 data.

These versions are available through the module tag 'may18' on the system at ECMWF, e.g. eccodes/may18, and will become the default ones on 22 May.


ecCodes version 2.7.3 provides full support for the new model output parameters introduced in IFS Cycle 45r1.


GRIB API version 1.26.0 provides full support for the new model output parameters introduced in IFS Cycle 45r1.

GRIB API is no longer loaded in the default user environment on the ECMWF systems. We will discontinue support for GRIB API at the end of 2018 and recommend to use ecCodes.


The version of EMOSLIB used to interpolate IFS Cycle 43r3 data is suitable to handle 45r1 data.

EMOSLIB is no longer loaded in the default user environment on the ECMWF systems.


Magics version 3.0.3 and  Metview version 5.0.2 provide full support for the new model output parameters introduced in IFS Cycle 45r1.

Availability of IFS 47r1 test data

Test data in MARS

Test data from the IFS Cycle 45r1 test suites are available in MARS. The data are available with E-suite experiment version (expver) 0072 (MARS keyword EXPVER=0072) starting from 06 UTC on 18 March 2018.

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 should not be used for operational forecasting.  Please report any problems you find with this data to User Support.

Test data in dissemination

IFS Cycle 45r1 test data from the release candidate testing stage are available through the test dissemination system. Users of ECMWF dissemination products can trigger transmission of test products by logging in to the test ECPDS system at  (or in the usual manner. In order to receive the test products, users have to have their firewall open to the relevant ECPDS Data Movers:

The IFS Cycle 45r1 test products are available as version number 72 (file names ending with '72'). The test products are generated daily, shortly behind real-time from both the 00UTC and 12UTC runs and based on the operational dissemination requirements and the IFS Cycle 45r1 test data for HRES, HRES-WAM, HRES-SAW., ENS, ENS-WAM and ENS extended..

Should you require any assistance with IFS Cycle 45r1 test dissemination products, please contact Data Services.

The derived products from the ENS (files named with dissemination stream indicator Y and U) are available in ECPDS. Cycle 45r1Tropical Cyclones data are missing in ECPDS and will be made available as soon as possible. 

The Cycle 45r1 new model output parameters listed above will be available through the dissemination after the implementation date. Users wanting to test these parameters will need to access them through MARS.

On the implementation date, we will freeze the access to the dissemination requirements interface for a few hours.

Web charts based on IFS cycle 45r1 test data

ENS meteograms based on IFS cycle 45r1 test data are available as of 16 May 2018 and can be viewed by selecting the "IFS cycle 45r1' model run in the ENS meteograms interface. Access to remaining web charts is now also available in the Charts Catalogue. Only the 'clickable' charts are available for the IFS cycle 45r1, by selecting the "IFS  cycle 45R1" from the Model run tab above the chart.

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 45r1 test data by using the limited ECaccess 'events' set up for this purpose:

Event ID

Event name


1633e_ms090At this stage, the e-suite step 090 (HRES-BC) has been generated.
1634e_ms144At this stage, the e-suite step 144 (ENS-BC) has been generated.
1635e_ms240At this stage, the e-suite step 240 (HRES) has been generated.
1636e_ms360At this stage, the e-suite step 360 (ENS) has been generated.
1637e_mslawAt this stage, the e-suite step law (HRES-SAW) has been generated.
1638e_ms1104At this stage, the e-suite step 1104 (ENS-MOFC) has been generated.
1639msrefcAt this stage, the e-suite step refc (REFORECAST) has been updated.

For these events, MSJ_EXPVER environment variable is set to 0072 and can be used to specify the IFS Cycle 45r1 test data in any MARS retrievals.

These events are  intended for testing technical aspects only and should not be used for operational forecasting.

Options 2 and 3

Option 2 or 3 time-critical applications can be tested with the IFS Cycle 45r1 test data retrieved from MARS or received in Dissemination.


Newsletter Number 156:

Document versions


Reason for update


Reason for update

  • Initial version
  • Scorecards available
  • Impact on Tropical cyclones added
  • Test data available in MARS, with some reservation on the MXCAPE and lightning parameters
  • Test data available in dissemination
  • New lightning and MXCAPE output parameters available
  • Re-forecasts available
  • Scorecards updated
  • ENS derived products available in ECPDS, with the exception of Tropical Cyclones
  • Data available in ecCharts
  • Change of bathymetry in cycle 45r1
  • Bug in GRIB-1 encoding fixed
  • ENS meteograms available
  • CAMS real-time system upgrade
  • Additional links for new parameters
  • New parameters in catalogues
  • Web charts available
  • Issue with encoding of Sea-Ice fraction analyses in MARS fixed.
  • Issue with Simulated Satellite imagery
  • Issue with Simulated Satellite imagery fixed on 02.06.2018
  • Implementation confirmed

titleContents of this page

Table of Contents

titleRelated links

titleAll IFS cycles

Children Display
pageChanges to the forecasting system