Description of upgrade

The CAMS IFS cycle 43R3 is based on ECMWF's IFS cycle 43R3. IFS Cycle 43r3 is an upgrade with many scientific contributions, including changes in the use of observations and in modelling. The new cycle only includes scientific changes; there are no technical changes, e.g. new resolutions. 

The page will be updated as required. It was last changed on 28.09.2017.

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.


Timetable for implementation

The planned timetable for the implementation of the cycle 43r3 is as follows:

26.07.2017Announcement of expected implementation date


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

Current Status

IFS cycle 43r3 has been implemented in operations on Tuesday 26 September 2017. We have discontinued the dissemination of the release candidate data.

Meteorological content of the new cycle

The meteorological changes can be found on the ECMWF IFS CY43R3 page.

Atmospheric composition content of the new cycle




Impact of the new cycle

The new cycle has been validated by the CAMS Validation team and the results are presented in a validation report. The main conclusions are: the new model configuration is an improvement as far as aerosols are concerned. Tropospheric ozone results for the o-suite and e-suite generally are very comparable, apart from a wintertime negative high-latitude bias (about 2-5 ppb) compared to the current operational version. This bias is largely related to changes (positive jump) in o-suite ozone that occurred on 24 January, the implementation day of the last upgrade. In spring, ozone values in the o-suite and e-suite are very similar. The other trace gas concentrations (CO, NO2, HCHO) show minor differences. Methane is improved.

Technical details of the new cycle

Changes to GRIB encoding

Model identifiers

The GRIB model identifiers (generating process identification number) for cycle 43R3 will be changed as follows:

Section 1
Section 4
grib_api key ComponentModel ID
6 14  generatingProcessIdentifierAtmospheric model147148
Ocean wave model112113
HRES stand-alone ocean wave model212213

The generatingProcessIdentifier for the Atmospheric Model for the initial dates (until 05 June 2017) is 147.

New model output parameters

There are no new parameters introduced with cycle 43r3.

Impact on users


The versions of EMOSLIB and GRIB API used to decode the existing operational cycle 43r1 data are suitable to handle the cycle 43r3 data as well.

Note that ecCodes has now replaced GRIB API on the ECMWF platforms.

Availability of test data from the cycle 43r3 test suites

Test data is available from MARS, either through direct access or through WebAPI. The CAMS operational FTP server (ECPDS) also serves daily test data in the directory "/DATA/CAMS_GLOBAL_TEST" and "/DATA/CAMS_EUROPE_BC_TEST" for global and regional boundary condition data, respectively. More details can be found here.

Document versions


DateReason for update
  • Initial version
  • Update of content description
  • Update to change list
  • Link to validation report
  • Announcement of implementation date
  • Cycle has been implemented