UM_Bristol

Solar forcing for HadCM3

Where to access data

You can find introduction of solar forcing from Homepage of SOLARIS-HEPPA, the CMIP7 Solar forcing, and the paper Funke et al., 2024.

Data can be access from links CMIP7 reference solar forcing dataset (1850-2023; monthly, CMIP7 reference solar forcing dataset (1850-2023; daily), and CMIP7 future solar forcing dataset (2022-2299; monthly); CMIP7 future solar forcing dataset (2022-2299; daily); and metadata.

To be noticed, the CMIP7 solar forcing provides reference data ranging from 1850-2023 (174 years in total. 1850-1873 for pre-industrial control; version 4.6) and future data ranging from 2022-2299 (version 4.6-a002). CMIP6 provides data from 1850-2299 (450 years in total; version 3.2).

However, the link for downloading CMIP6 solar forcing data are now overwritten by the CMIP7 one. But you can access data from my previous saved file: monthly resolution reference solar forcing for CMIP6.

How to process data

Total Solar Irradiation (TSI)

The HadCM3B model requires time-varying Total Solar Irradiation (TSI) file in annual mean resolution, saving as a .dat file with two columns (year value), without column name. So we need to convert the original monthly data into annual mean format. You can use this python script to convert and plot data: Convert_TSI_data.ipynb

You can get the converted annual mean varying_TSI_CMIP6.dat file, for example, from local path (can be opened with Notepad), or in BC4:/user/home/mf22281/um_updates/.

The file looks like this:
head of varying_TSI_CMIP6 file.png

TSI data for CMIP6:

TSI data for CMIP7_reference:

Comparisons of CMIP6 and CMIP7_reference TSI data: TSI_CMIP6&7_1.png

TSI_CMIP6&7_2.png

How to implement the forcing into HadCM3

Setup a transient TSI job

Tutorial: Tutorial of Solar Orbit Setup_202503.docx

Key process:

copy a standard HadCM3B job.
setup a module in PUMA2, UMUI window:

Model Selection
-> sub-model independent
-> compilation and modification
-> modifications for the model
-> Fortran Mods table |Fortran modes | Include Y/N | |————–|————-| |$PV_UPDATES/solar_orbit_real1950.mod|Y|

Where $PV_UPDATAES: BC4:/mnt/storage/private/bridge/swsvalde/um_updates/

Include time-varying TSI file and turn on related options in PUMA2, UMUI window:

Model Selection
-> sub-model independent
-> Script inserts and modifications
-> Defined Environment Variable

L_SEC_VAR: .TRUE.: set orbit changing through time
L_SOLAR_SPEC: .TRUE.: set solar spectrum changing through time
ORB_REAL_YEAR: 0
ORB_OFFSET_YEAR: 0
SOLAR_FILE: /home/mf22281/um_updates/varying_TSI_CMIP6.dat (change file path and name as you want)

save
process
copy job from PUMA2 to BC4:~/umui_jobs/

You can further check or modify the setting in BC4:~/umui_jobs/jobid/MODS_UM:

BC4:~/umui_jobs/jobid/CNTLATM:

BC4:~/umui_jobs/jobid/SCRIPT:

Setting

Control run: xqcpz

A copy of the standard HadCM3B job, tdaag, which is HadCM3-MOSES2.1-TRIFFID_dyn, Pre-industrial.
Solar constant = 1361.0 $W/m^2$.
re-run from year 1850 to 2299.
check setting and results of xqcpz and xqcpz-tdaag here

Test effectivess of solar setting: xqcpb

solar file set as BC4:/user/home/mf22281/um_updates/shift_TSI.dat.
This job is used to test the effectiveness of the solar setting.
This solar file set the TSI values start from 1361 $W/m^{2}$ for 20 years, then suddenly shift to a larger value (1391 $W/m^{2}$) for 10 years, then shifts back to 1361 $W/m^{2}$ for the remaining years.
Set running from year 1850 to 2299.
check setting and results of xqcpb and xqcpb-xqcpz here

Test with CMIP6_TSI: xqcpa

solar file set as BC4:/user/home/mf22281/um_updates/varying_TSI_CMIP6.dat
running from year 1850 to 2299.
check setting and results of xqcpa and xqcpa-xqcpz here

Test with CMIP7_TSI_ref: xqcpc

solar file set as BC4:/user/home/mf22281/um_updates/varying_TSI_CMIP7.dat running from year 1850 to 2023. check setting and results of xqcpc and xqcpc-xqcpz here

Test with CMIP7_TSI (reference + future): xqcpd

solar file set as BC4:/user/home/mf22281/um_updates/xxx? running from year 1850 to 2299. check setting and results of xqcpd and xqcpd-xqcpz here. (To be update…)