The IFS uses an aerosol climatology in most configurations and prognostic aerosols in operational CAMS forecasts.
- From 43r3 to 49r1, the IFS used a 3D climatology varying with latitude, longitude and pressure (as well as month of the year): https://aux.ecmwf.int/ecpds/home/radiation/aerosol_climatology/aerosol_cams_climatology_43r3_v2_3D.nc described by Bozzo et al. (2020, https://gmd.copernicus.org/articles/13/1007/2020/).
- From 49r2, the IFS uses a 3D climatology adding an additional dimension "epoch" to represent the long-term variations in anthropogenic aerosols: https://aux.ecmwf.int/ecpds/home/radiation/aerosol_climatology/aerosol_cams_climatology_49r2_1951-2019_4D.nc
The optical properties are defined in a file that has multiple options for each aerosol type, the latest of which is: aerosol_ifs_49R2.nc. In the IFS the required optical property model is looked-up by aerosol type, bin number, whether hydrophilic or hydrophobic, and model name. In offline ecRad, the optical model needs to be specified using indices (starting at 1) to the types in the optical property file using positive numbers for the hydrophobic types and negative numbers for the hydrophilic types). The following table lists the optical models used in the two climatologies, as well as the prognostic aerosol scheme since CAMS 49r1. The numbers provide the indices to the optical models.
| Aerosol type | Climatology from 43r3 | Prognostic CAMS 47r3 | Prognostic CAMS 48r1 | Climatology from 49r2 | Prognostic CAMS from 49r1 |
| Desert dust (DD) | Woodward2001 (7,8,9) | Woodward2001 (7,8,9) | Composite (15,16,17) | Composite (15,16,17) | CompositePhiSca (now hydrophilic!) (-14,-15,-16) |
| Black carbon (BC) | OPAC (11) | OPAC (11) | OPAC (11) | OPAC (11) | Bond2006 (12) |
| (Primary) Organic matter (OM) | OPAC (-4,10) | OPAC (-4,10) | Brown2018 (-11,18) | Brown2018 (-11,18) | Brown2018 (-11,18) |
| Sulfate (SU) | GACP (-12) | GACP (-12) | GACP (-12) | GACP-NewPSD (-13)* | GACP-NewPSD (-13) |
| Sea salt (SS) | OPAC (-1,-2,-3) | OPAC (-1,-2,-3) | OPAC (-1,-2,-3) | OPAC (-1,-2,-3) | OPAC (-1,-2,-3) |
| Nitrate (NI) | GLOMAP (-9,-10) | GLOMAP (-9,-10) | GLOMAP (-9,-10) | GLOMAP (-9,-10) | |
| Ammonium (AM) | GACP (-8) | GACP (-8) | GACP (-8) | GACP (-8) | |
| Biogenic secondary organic (OB) | Moise2015 (-6) | Moise2015 (-6) | Moise2015 (-6) | ||
| Anthropogenic secondary organic (OA) | Moise2015 (-7) | Moise2015 (-7) | Moise2015 (-7) |
*Please note that the 49r2 climatology has been configured to use the updated (GACP-NewPSD) Sulfate optical properties, but perhaps for consistency with the prognostic CAMS 48r1 from which it was derived, it should have used the original GACP.