Table of Contents

Description of upgrade

The CAMS IFS cycle 50R1 is based on ECMWF's IFS Cycle 50r1. 

The CAMS datasets affected by the upgrade are:

  • CAMS global atmospheric composition forecasts (COMPO)
  • CAMS global greenhouse gas forecasts (GHG)

Timetable for implementation

The planned timetable for the implementation of the cycle 50R1 is as follows:

DateEvent
late April 2025Implementation


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

Current Status

IFS cycle 50R1 is going through its final preparation phase.

Meteorological content of the new cycle

The meteorological changes can be found on the ECMWF IFS CY50R1 page.

Atmospheric composition and greenhouse gas upgrades of the new cycle

Assimilation

  • Updated background errors for NWP, now taken from the operational EDA (COMPO)
    Updated background errors for O3 to remove spurious long-range correlations (COMPO)
  • The EDA-based B matrix used in 49r1 is tapered in the stratosphere for 50r1 for CH4  (GHG)
  • The EDA-based B matrix used in 49r1 is tapered near the surface in 50r1 for CO2 (GHG)

Observations

  • Sentinel 3 AOD over ocean actively assimilated (COMPO)
  • TROPOMI for CH4 (GHG) 

Emissions

  • CAMS-GLOB-ANT-M1,  a merged emission data set using regional emissions inventories for North-America (EPA), Europe (CAMS-REG) and China (MECS)  and Edgar 6.2 elsewhere (COMPO) 
  • Activation of weekly cycle in anthropogenic emissions 
  • Online BVOC emissions simulation   (COMPO)
  • New GFAS emissions 1.4.2 (MODIS and VIIRS-based)   

Model changes

Aerosol developments (COMPO): 

  • Implementation of an equilibration time parameterization for nitrate/ammonium formation
  • Revision of hydrophilic growth of OM, SOA and fine mode nitrate
  • Correction of hydrophilic growth factor of sea salt for sedimentation
  • Sedimentation velocity computed online for all species, using the Stokes formula

Reactive gases developments (COMPO):  

  • Update of heterogeneous chemistry parameterization
  • Revision of SO2 + H2O2 aqueous phase reaction

Technical details of the new cycle

Change to GRIB encoding

The GRIB model identifiers (generating process identification number) for cycle 50r1 will be changed as follows:

GRIB 1

Section 1

Octets

GRIB 2

Section 4

Octets

ecCodes key 

Component

Model identifier

49r1

50r1

6

 14  

generatingProcessIdentifier

Atmospheric model

158

161

6

 14  

generatingProcessIdentifier

Ocean wave model

106

109

For all parameters in GRIB 2 the Master Tables Version Number will be changed as follows:

GRIB 2

Section 1

Octets

ecCodes key 

Master Tables Version Number

49r1

50r1

 10 

tablesVersion

33

35

Software

To handle the data of Cycle 50r1 we recommend to use the ECMWF software packages 

ecCodes  (2.44.0)
CodesUI  (minimum version)
Magics  (4.16.0)
Metview  (5.26.1)
ODC  (1.6.0)

On the ECMWF HPC these versions correspond to ecmwf-toolbox/2025.1

Availability of test data from the cycle 50r1 test suites

The CAMS operational ECMWF data portal (aux.ecmwf.int; SFTP/FTP/HTTPS data access) will serve the most recent 3 days of test data, once the e-suite is running in near-real-time, in the directories "/DATA/CAMS_GLOBAL_TEST" and "/DATA/CAMS_EUROPE_BC_TEST" for global and regional boundary condition data, respectively.

In addition, surface level fields (model level 137) will be provided as individual files in the "/DATA/CAMS_GLOBAL_ADDITIONAL_TEST" directory. 

Users wanting to access the output from the current test system for a longer period can access the data from 05-2025 onwards directly on MARS or through the Atmosphere Data Store. More details can be found here: Accessing CAMS 50r1 test data.


This document has been produced in the context of the Copernicus Atmosphere Monitoring Service (CAMS).

The activities leading to these results have been contracted by the European Centre for Medium-Range Weather Forecasts, operator of CAMS on behalf of the European Union (Delegation Agreement signed on 11/11/2014 and Contribution Agreement signed on 22/07/2021). All information in this document is provided "as is" and no guarantee or warranty is given that the information is fit for any particular purpose.

The users thereof use the information at their sole risk and liability. For the avoidance of all doubt , the European Commission and the European Centre for Medium - Range Weather Forecasts have no liability in respect of this document, which is merely representing the author's view.

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