noresm:runmodel:cmip6_volcanic_forcing

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CMIP6 volcanic forcing

The CMIP6 volcanic forcing implementation has been committed to both the noresm (CESM1.2) and the noresm-dev (CESM2_beta) repository. The commits can be viewed here:
https://github.com/metno/noresm/commit/59d2b4c4714c0df41141a10d79fd329b27b8aed6
https://github.com/metno/noresm-dev/commit/bbec72fa49ed57ab70d5052b8b4c0162eeb6ab88

SourceMods are available on FRAM/NIRD:
<span style="font-family:monospace;font-size:125%">/nird/projects/fram/nn2345k/ingo/CMIP6/Forcing/Volc/SourceMods_noresm_cesm1.2</span>
<span style="font-family:monospace;font-size:125%">/nird/projects/fram/nn2345k/ingo/CMIP6/Forcing/Volc/SourceMods_noresm_cesm2beta6</span>

The folder <span style="font-family:monospace;font-size:125%">SourceMods_noresm_cesm2beta6</span> also contains a modified version of CAM's <span style="font-family:monospace;font-size:125%">build-namelist</span> script that needs to be installed in <span style="font-family:monospace;font-size:125%">components/cam/bld/</span>.

For certain compsets the below specifications are applied as automatically. Still, there is no harm in putting the same settings in your <span style="font-family:monospace;font-size:125%"> user_nl_cam </span> in your case directory.

Specify following in your <span style="font-family:monospace;font-size:125%"> user_nl_cam </span> to activate the use of CMIP6 compliant volcanic background forcing:

! Users should add all user specific namelist changes below in the form of
! namelist_var = new_namelist_value
 prescribed_volcaero_datapath           = '/cluster/shared/noresm/inputdata/atm/cam/volc'
 prescribed_volcaero_file               = 'CMIP_CAM6_radiation_average_v3_reformatted.nc'
 prescribed_volcaero_cycle_yr           = 1850
 prescribed_volcaero_type               = 'CYCLICAL'
 rad_climate            = 'A:Q:H2O', 'N:O2:O2', 'N:CO2:CO2', 'N:ozone:O3', 'N:N2O:N2O', 'N:CH4:CH4', 'N:CFC11:CFC11', 'N:CFC12:CFC12'
 fincl1 = 'AODVVOLC', 'ABSVVOLC' 

Note that <span style="font-family:monospace;font-size:125%"> rad_climate </span> is specified because CAM's <span style="font-family:monospace;font-size:125%">build-namelist</span> script will otherwise add an extra entry that was needed by the CMIP5 volcanic forcing implementation.

Specify following in your <span style="font-family:monospace;font-size:125%"> user_nl_cam </span> to activate the use of CMIP6 compliant transient (1850-2014) volcanic forcing:

! Users should add all user specific namelist changes below in the form of
! namelist_var = new_namelist_value
 prescribed_volcaero_datapath           = '/cluster/shared/noresm/inputdata/atm/cam/volc'
 prescribed_volcaero_file               = 'CMIP_CAM6_radiation_v3_reformatted.nc'
 rad_climate            = 'A:Q:H2O', 'N:O2:O2', 'N:CO2:CO2', 'N:ozone:O3', 'N:N2O:N2O', 'N:CH4:CH4', 'N:CFC11:CFC11', 'N:CFC12:CFC12'
 fincl1 = 'AODVVOLC', 'ABSVVOLC' 

The only difference to the CESM1.2 setting is that following extra specification needs to be specified in the case's <span style="font-family:monospace;font-size:125%"> user_nl_cam</span>:

 prescribed_strataero_file              = ' '

This will deactivate the use of NCAR's alternative CMIP6 volcanic forcing. CAM's original <span style="font-family:monospace;font-size:125%">build-namelist</span> script does not properly recognise the deactivation and will issue an error that both <span style="font-family:monospace;font-size:125%">prescribed_strataero_file</span> and <span style="font-family:monospace;font-size:125%">prescribed_volcaero_file</span> are set.

As a workaround, replace <span style="font-family:monospace;font-size:125%">components/cam/bld/build-namelist</span> in your model tree with the modified version <span style="font-family:monospace;font-size:125%">/nird/projects/fram/nn2345k/ingo/CMIP6/Forcing/Volc/SourceMods_noresm_cesm2beta6/build-namelist </span>

The complete set of optical parameters of the volcanic forcing can be written to the monthly history output by adding following in the case's <span style="font-family:monospace;font-size:125%"> user_nl_cam</span>:

 
fincl1 = 'ext_sun1','ext_sun2','ext_sun3','ext_sun4','ext_sun5','ext_sun6','ext_sun7','ext_sun8','ext_sun9','ext_sun10','ext_sun11','ext_sun12','ext_sun13','ext_sun14','omega_sun1','omega_sun2','omega_sun3','omega_sun4','omega_sun5','omega_sun6','omega_sun7','omega_sun8','omega_sun9','omega_sun10','omega_sun11','omega_sun12','omega_sun13','omega_sun14','g_sun1','g_sun2','g_sun3','g_sun4','g_sun5','g_sun6','g_sun7','g_sun8','g_sun9','g_sun10','g_sun11','g_sun12','g_sun13','g_sun14','ext_earth1','ext_earth2','ext_earth3','ext_earth4','ext_earth5','ext_earth6','ext_earth7','ext_earth8','ext_earth9','ext_earth10','ext_earth11','ext_earth12','ext_earth13','ext_earth14','ext_earth15','ext_earth16','omega_earth1','omega_earth2','omega_earth3','omega_earth4','omega_earth5','omega_earth6','omega_earth7','omega_earth8','omega_earth9','omega_earth10','omega_earth11','omega_earth12','omega_earth13','omega_earth14','omega_earth15','omega_earth16','g_earth1','g_earth2','g_earth3','g_earth4','g_earth5','g_earth6','g_earth7','g_earth8','g_earth9','g_earth10','g_earth11','g_earth12','g_earth13','g_earth14','g_earth15','g_earth16'
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  • noresm/runmodel/cmip6_volcanic_forcing.1513285874.txt.gz
  • Last modified: 2022-05-31 09:23:24
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