CCMI-2022 recommendations

CCMI-2022 recommendations


Solar forcing recommendations are based on CMIP6 recommendations Version 3.2 (Matthes et al., 2017, Geosci. Model Dev., 10, doi:10.5194/gmd-10-2247-2017) for the historical experiments (1850-2014). The CMIP6 solar forcing reconstruction for the historical period has been extended to include the period 1/1/2015 - 31/12/2019 using identical methods and approaches that were applied to the original CMIP6 dataset.

The CCMI-2022 solar forcing data includes the following forcing components with daily resolution for the period 1/1/1950 - 31/12/2019:

Irradiance forcing

TSI:     Total solar irradiance
F10.7: F10.7 cm solar radio flux
SSI:    Spectral solar irradiance for 10-100,000 nm range

Particle forcing:

Ap:   Daily planetary Ap-index
Kp:   Daily planetary Kp-index
iprp:  Ion-pair production rate by solar protons
iprg:  Ion-pair production rate by galactic cosmic rays
iprm: Ion-pair production rate by medium-energy electrons


A detailed description of how the data were constructed as well as a “technical” documentation of the files’ structures, dimensions, variable names, etc. can be found here.

More detailed information and auxiliary software packages for data pre-prossessing are available at the SOLARIS-HEPPA CMIP6 solar forcing page. 

Data access:

All data are provided in zipped netcdf (HDF5) files. For those models that do require only a subset of the forcings, these are to be selected from the provided files by the user.

Please note that in order to account for solar cycle effects, not only radiative effects but also photochemical effects have to be taken into account!

For consideration of Energetic Particle Precipitation (EPP) in chemistry climate models with upper lid in the mesosphere (i.e., below the EPP source region), a NOy Upper Boundary Condition (UBC) is required in order to account for the EPP indirect effect (polar winter descent of EPP-generated odd nitrogen).

The following package contains a routine for generation of a flux or density NOy-UBC from geomagnetic Ap data which is included in the solar forcing datasets. Output data is written to a netcdf file as daily resolved NOy zonal mean densities (in units of cm-3) or molecular fluxes (in units of cm-2 s-1) on model-specific pressure levels and bin center latitudes. The routine is available in IDL or MATLAB.