DRAFT

Description of upgrade

The CAMS IFS cycle 49R1 is based on ECMWF's  IFS Cycle 49r1. This is an upgrade with a limited number of scientific contributions for the atmospheric composition aspects. Key elements are an update of the global emissions to the CAMS-GLOB-ANT 6.1 dataset and improvements to the modelling of aerosol.  More information can be found below.

The page will be updated as required. It was last changed on 13 September 2024.

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 our User Support.

Timetable for implementation

The planned timetable for the implementation of the cycle 49r1 is as follows:

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

Current Status

IFS cycle 49r1 is going through its final preparation phase.

Meteorological content of the new cycle

The meteorological changes can be found on the ECMWF  IFS CY49R1 page.

Atmospheric composition content of the new cycle

Assimilation

• No updates

Observations

• IASI SO2 data with altitude information assimilated into volcanic SO2 tracer
• Passive monitoring of OMPS SNPP limb profiler O3 data
• Passive monitoring of NOAA-21 OMPS nadir-profiler O3 data
• Passive monitoring of GEMS O3 and NO2 data

• Change in passively monitored TROPOMI HCHO data to include negative values when creating averaged observations

Emissions

• CAMS-GLOB-ANT 5.3 (based on EDGAR 5, used in 48r1) has been replaced by CAMS-GLOB_ANT 6.1 (based on EDGAR 6 and 7)
• CAMS-GLOB-BIO 3.1 climatology (as in 48r1 )  
• CAMS-GLOB-Soils 2.4  (was "old" POET-based soil NOx)
• CAMS-GLOB-VOLC-CLIM (2005-2021)  (was old climatology based on Carn et al., 2017) 
• GFAS emissions fix to reduce NOx emissions in boreal regions and NH3 in tropical peat fire regions, to correct for outdated emission factors  

Model changes

Aerosol developments: 

• EQSAM4Clim module activated for gas-phase aerosol partitioning
• computation of aerosols, cloud and precipitation pH
• use of online cloud pH in aqueous chemistry, of online precipitation pH in wet deposition of relevant chemical species
• use of a temperature dependent activation function to determine the fraction of hydrophilic aerosol subjected to wet deposition in mixed clouds 
• coupled stratospheric sulphate aerosol formation with BASCOE gas-phase chemistry. 
• revised carbonaceous aerosol (OM and BC) aging scheme (from hydrophobic to hydrophilic) 
• new aerosol optical properties to account for hydrophilic and aspherical dust
• use of convective gusts in the dust emission scheme
• assumed size distribution consistent with optics - revised PM2.5 formulae to reflect this
• implementation of the Gong 03 sea-salt aerosol emission scheme to replace Monahan 1986 (applied on the whitecap fraction computed with the Albert 16 scheme)
• updates of dust source function 

Reactive gases developments:  

• Updates to photolysis quantum yields and cross sections for selected trace gases in troposphere  
• Tuning of ozone depletion modeling in the stratosphere
• dry deposition scheme to use IFS stomatal resistance 
• De-activation of dry deposition of CO
• Lopez-lightning emission parameterisation for Lightning Nox emissions  

Impact of the new cycle

A comprehensive evaluation report of the 49r1 e-suite, documenting all the changes and their impact on the forecasts will be provided ahead of the actual implementation. Initial testing results show improved aerosol forecasts.

Technical details of the new cycle

New and discontinued parameters

Several of the upgrades in CY49R1 have resulted in new parameters, some of which will be added to the dissemination through the Atmosphere Data Store (ADS) and the ECPDS ftp server. For now, the main new parameters are listed in the table below. Others might be added based on user requests. (any changes?)

Change to GRIB encoding

The GRIB model identifiers (generating process identification number) for cycle 49r1 will be changed as follows:

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

Software

To handle the data of Cycle 49r1 we recommend to use the ECMWF software packages 

ecCodes 2.36.0 (minimum version 2.35.1)
CodesUI 1.8.0 (minimum version 1.7.3)
Magics 4.15.4 (minimum version 4.13.0)
Metview 5.22.1 
ODC 1.5.2 (minimum version 1.4.6)

On the ATOS HPC these versions correspond to ecmwf-toolbox/2024.06.0.0.

Availability of test data from the cycle 49r1 test suites

Document versions