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A global production system is also used to assimilate re-processed observations from many satellites for the last few decades, using the same data assimilation process. The result is called reanalysis and it provides a consistent data set that can be used for scientific studies and trend analyses. The current atmospheric composition reanalysis produced by the Copernicus Atmosphere Monitoring Service is the CAMS: Reanalysis data documentation (EAC4).

The IFS model and data assimilation system configurations (

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49r1)

The model used in the CAMS Global atmospheric composition forecast is the Integrated Forecasting System (IFS) that also produces ECMWF weather forecasts, but with additional modules enabled for aerosols, reactive gases and greenhouse gases that have been developed within CAMS and precursor projects GEMS and MACC. The following processes of atmospheric composition are considered:

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  • anthropogenic emissions from the CAMS_GLOB_ANT v5v6.3 1 with sectoral diurnal cycles and injection heights
  • natural and biogenic emissions from the CAMS_GLOB_BIO v3.1 climatologies
  • emissions from soils from the CAMS-GLOB-Soils 2.4 dataset
  • volcanic emissions from the CAMS-GLOB-VOLC-CLIM (2005-2021) dataset
  • ocean fluxes of DMS from the CAMS_GLOB_OCE v.3.1 climatology
  • aircraft emissions of CO2 and NOx from the CAMS_GLOB_AIR v3.1 data set
  • biomass burning emissions inferred from satellite observations of fire activity from the CAMS GFAS v1.4 system
  • using IS4FIRES injection heights from the CAMS GFAS v1.4 system

For details about simulations and assimilation of chemistry, carbon dioxide, methane and aerosols please see References.methane and aerosols please see References. Major upgrades of the 49r1 are:

Data assimilation developments: 

  • IASI SO2 data with altitude information assimilated into volcanic SO2 tracer

  • Passive monitoring of GEMS O3 and NO2 data

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
  • coupled stratospheric sulphate aerosol formation with BASCOE gas-phase chemistry. 
  • new aerosol optical properties to account for hydrophilic and aspherical dust

Reactive gases developments:  

  • Updates to photolysis quantum yields and cross sections for selected trace gases in troposphere  
  • Lopez-lightning emission parameterisation for Lightning Nox emissions  

The IFS uses a four-dimensional variational data assimilation method (4D-VAR) for the assimilation of a wide range of meteorological observations as well as satellite retrievals of atmospheric composition.

The IFS model documentation for various model cycles can be found on https://www.ecmwf.int/en/publications/ifs-documentation, including a new section on atmospheric composition aspects. Please note that the IFS cycle changes during the years, and this page documents the current most recent operational cycle (48r1); please have a look at the table below for details of changes from previous cycles.

The report on the the evaluation of the 49r1 e-suite is available in the here.

Configuration for CAMS Global atmospheric composition global forecasts (daily)

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The IFS undergoes changes regularly in order to improve the forecast. Changes are listed below with their identifier (Cycle 46r1 for instance) or a specific title when the cycle number did not change.

Implementation dateCycleSummary of changesResolution/Resolution changeNew species
12 November 202449r1

Atmospheric composition, Meteorology

Horizontal: 40km, Vertical: 137 levels

none

27 June 202348r1

Atmospheric composition, Meteorology, GRIB encoding

Horizontal: 40km, Vertical: 137 levels

See parameters in green in tables below

1 Feb 202347r3Assimilation of AOD from VIIRS 
none
15 Dec 202247r3Update of the T159 background error covariance wavelet file to use the correct NWP background errors. The update leads to considerably improved NWP forecast scores.  As a consequence, smaller changes to AOD and upper tropospheric and lower stratospheric ozone are also expected.Horizontal: 40km, Vertical: 137 levelsnone
22 Feb 202247r3A fix of low-level T/q in fog conditions was introduced with the 12 UTC cycle on 22 Feb 2022Horizontal: 40km, Vertical: 137 levelsnone
12 October 202147r3Atmospheric composition, MeteorologyHorizontal: 40km, Vertical: 137 levelsnone
18 May 2021 (12UTC cycle)47r2Atmospheric composition, MeteorologyHorizontal: 40km, Vertical: 137 levelsnone
6 October 202047r1Atmospheric composition, MeteorologyHorizontal: 40km, Vertical: 137 levelsnone
9 July 201946r1Atmospheric composition, MeteorologyHorizontal: 40km, Vertical: from 60 to 137 levelsAerosols: nitrate and ammonium
26 June 201845r1Atmospheric composition, MeteorologyHorizontal: 40km, Vertical: 60 levelsSee Table 1 and 2
26 September 201743r3Atmospheric composition, MeteorologyHorizontal: 40km, Vertical: 60 levelsnone
24 January 201743r1Atmospheric composition, MeteorologyHorizontal: 40km, Vertical: 60 levelsnone
21 June 201641r1Atmospheric composition, MeteorologyHorizontal: from 80km to 40km, Vertical: 60 levelsnone

Data access

The data is now available from the Atmosphere Data Store (ADS), either interactively through its download web form or programmatically using the CDS API service:

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Access to CAMS global air quality forecast and analysis data through the ECMWF the ECMWF public Web API service ended on 30 June 2021.

To move to the ADS service, please follow our guidelines on How to migrate to CDS API on the Atmosphere Data Store (ADS).

Users with direct access to MARS can browse the data on the MARS catalogue under class=mc and expver= 0001.

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Fast accessParameters labelled as "Fast access" are stored on disk while parameters labelled as "slow access" are stored on tape. Retrieval of this data will be MUCH SLOWER than disk-resident data.

Parameters highlighted in green were introduced with the new 48R1 upgrade (48R1).


Note

PLEASE NOTE: *Total column (in kg m-2) is available at the surface (model level 137 for MARS users; before 9 July 2019, model level 60). Total column refers to the total amount of the selected variable in a column of air extending from the surface of the Earth to the top of the atmosphere (model level 1 for MARS users). Total column can also be referred to as total <selected variable>, or vertically integrated <selected variable>.

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Issue typeDescriptionCycleNote
Time-integrated deposition fluxes for chemical species have zero values

The time-integrated dry and wet deposition fluxes for chemical species with GRIB codes starting with 222 and 223 have zero values for all the times. These fields have data start from June 2023.

48r1
High SO2 values over north-eastern Brazil

High SO2 values over north-eastern Brazil on 18 January 2020 and 16 June 2020 at 06:00:00 are artificial and are due to the assimilation of some spurious satellite observations of SO2 in one of the datasets used by CAMS. 

47r1
BC concentrations in the mid/upper troposphere tend to be too high

Some of the low background BC concentrations in the mid/upper troposphere tend to be too high as an artefact of the data assimilation as it improves the total AOD. (They're still very low compared to polluted areas, but can be somewhat higher than they should.) This aspect of the impact of data assimilation on aerosol speciation is something that we're continuing to look into. (The accompanying "control run", a model-only product with no AOD assimilation, can often has a more realistic speciation and vertical profile in this regard, but at the cost of a poorer agreement with observations of total AOD.)

47r1 or 46r1

Dust emissions are too high in cycle 46r1

See details here: Dust emissions are too high in Cycle 46r146r1

AOD and PM data are zero at forecast step 0

Aerosol optical depth (AOD) and particulate matter (PM10, PM2.5) at forecast step 0: all values are zero41r1 and 43r1

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How to cite the data

All users of data uploaded on the Atmosphere Data Store (ADS) must provide clear and visible attribution to the dataset provider and the Copernicus programme. Please make sure that (1) you acknowledge according to the dataset licence, (2) you indicate that you have downloaded the dataset from the ADS, and (3) you provide a citation of the dataset.


  1. Please acknowledge the use of the CAMS as stated in the Licence to Use Copernicus Products:

    false

    • "Where the Licensee communicates to the public or distributes or publishes CAMS Information, the Licensee shall inform the recipients of the source of that information by using the following or any similar notice:

      'Generated using Copernicus Atmosphere Monitoring Service Information [Year]'

    • Where the Licensee makes or contributes to a publication or distribution containing adapted or modified CAMS Information, the Licensee shall provide the following or any similar notice:

      'Contains modified Copernicus Atmosphere Monitoring Service Information [Year]';

    Any such publication or distribution shall state that "neither the European Commission nor ECMWF is responsible for any use that may be made of the information it contains."


  2. Indicate where data was downloaded from:

    false

    <authors> (year of publication) data downloaded from the Copernicus Atmosphere Monitoring Service (ADS) Atmosphere Data Store (ADS) (doi or url)


  3. Cite each dataset version (as applicable): 
false

check with Johannes. Format is:Surname, initial., Surname, Initial. (Year of publication): <title as shown in ADS>, <version number if applicable>, Copernicus Atmosphere Monitoring Service (CAMS) Atmosphere Data Store (CDS). (<date of access>), xxx.


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