Solar

Key contacts

Summary

The CMIP7 version of the solar dataset has been released. If you find any problems, please raise an issue. Discussions on this and earlier versions can be found in https://github.com/PCMDI/input4MIPs_CVs/discussions/19.

Source IDs for CMIP7 phases

The source ID that identifies the dataset to use in CMIP7 is given below.

CMIP7

For the CMIP7 phase of CMIP7, use data with the source ID SOLARIS-HEPPA-CMIP-4-6

This data is for use in CMIP7 production simulations. All data sets for use in CMIP7 production simulations are published with a mip_era metadata value of ‘CMIP7’. This metadata value appears both in the file’s global metadata as well as its metadata on ESGF.

If you find an issue, please create an issue on GitHub so that the identification and resolution of this issue is publicly accessible.

Testing

For the testing phase of CMIP7, use data with the source ID SOLARIS-HEPPA-CMIP-4-5

This data is for testing (both of the forcing data and of modelling workflows) only. Production simulations should not be started based on any data that has a mip_era value equal to ‘CMIP6Plus’. (The mip_era metadata value appears both in each file’s global attributes as well as its metadata on ESGF.)

If you have any feedback, please add it to the relevant GitHub discussion.

Recommendation for pre-industrial control

There is a dedicated pre-industrial control file. See the files with fx in their name (fx stands for fixed, which is used because the pre-industrial control file is a fixed field, custom for the pre-industrial control experiment).

Grids and frequencies provided

The data is provided on a wavelength, pressure level and latitudinal grid. The data is provided with two frequencies: monthly and daily.

Species provided

Multiple variables are provided, please see the files for the full list and information. Of particular interest for many is total solar irradiance (tsi), which provides the total solar irradiance at 1 AU.

Uncertainty

At present, we provide no analysis of the uncertainty associated with these datasets. This is a work in progress, we hope to provide that data when it is available.

Differences from CMIP6 or other previous versions

File formats and naming

The file formats are generally close to CMIP6. The key change is in the file naming. The files are now named according to the DRS, but this does make it harder to tell which file is which at first glance. The pre-industrial control file is a fixed field, hence has fn in the filename (although even this is not 100% accurate, but we have avoided changing it to minimise downstream headaches, for details, see https://github.com/PCMDI/input4MIPs_CVs/issues/184). The two different frequencies are also distinguished in the filename, mon for monthly data and day for daily data.

Data

There are some changes from CMIP6. The CMIP6 data can be found on the ESGF under the “CMIP6” project and source ID “SOLARIS-HEPPA-3-2”. Funke et al., GMD 2024 provides a detailed analysis of the changes from earlier versions.

Revision history

SOLARIS-HEPPA-CMIP-4-4

v4.5 resolves issues with MEE short-term variability. Hence v4.4 is retracted. There are no changes to SSI/TSI (so, if you have used v4.4 for SSI/TSI, you do not need to restart). The original comment from the data provider is here. For further information, see SOLARIS-HEPPA release notes.

SOLARIS-HEPPA-CMIP-4-3

v4.4 uses the final, absolute TSI scale (in consonance with NNL1) which should be used in CMIP7. Hence v4.3 is retracted. The change between v4.3 and v4.4 results in a 179 ppm increase of TSI and SSI compared to version 4.3. The preliminary TSI/SSI version in 4.3 had adapted the TSI scale from the CTIM instrument alone, the newer TSI scale is based on a TSIS-1 and CTIM composite (Coddington and Lean, 2024). This composite is also consistent with the TSI ‘community consensus’ composite (spot.colorado.edu/~koppg/TSI/TSI_Composite-SIST.txt). The original comment from the data provider is here. For further information, see SOLARIS-HEPPA release notes.

SOLARIS-HEPPA-CMIP-4-2

An issue was encountered with the proton ionization data in v4.2. It was hence retracted. The original comment from the data provider is here.