source: CMIP6/RFMIP/piClim-control/CM616-LR-piClim-control5-2RadCall/README_2RadCall_GHG @ 5213

A 2nd radiation call is performed for GHG only, 
in order to compute IRF at TOA, SRF and at the tropopause.

NOTE the lmdz.card particularities :
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1/ The GHG set is changed every 5 years of run cf lmdz.card, 
in order to calculate the corresponding IRFs in a piClim-control climate :

[SmoothFiles]
List=   (${SUBMIT_DIR}/PARAM/config.def_${ConfType}_GHGpd_CO2pi,  config.def, 1:1:5),  \
        (${SUBMIT_DIR}/PARAM/config.def_${ConfType}_GHGpi_CO2pd,  config.def, 6:1:10), \
        (${SUBMIT_DIR}/PARAM/config.def_${ConfType}_GHGpd,  config.def, 11:1:15),  \
        (${SUBMIT_DIR}/PARAM/config.def_${ConfType}_2xCO2,  config.def, 16:1:20),  \
        (${SUBMIT_DIR}/PARAM/config.def_${ConfType}_3xCO2,  config.def, 21:1:25),  \
        (${SUBMIT_DIR}/PARAM/config.def_${ConfType}_4xCO2,  config.def, 25:1:)

Radiation variables from 2nd call have all the "ghg" suffixe (no matter the GHG combination).

2/ Customized xml files are used, 
  with groups of 2D and 3D variables from 1st and 2nd radiation call, needed for calculating IRF TOA and SFC, 
  and *tropopause variables needed for IRF at tropopause : 
  [ParametersFiles]
        (${SUBMIT_DIR}/PARAM/context_lmdz.xml_2RadCall, context_lmdz.xml ),            \
        (${SUBMIT_DIR}/PARAM/field_def_lmdz.xml_2RadCall, field_def_lmdz.xml ),          \
        (${SUBMIT_DIR}/PARAM/file_def_histmth_lmdz.xml_2RadCall, file_def_histmth_lmdz.xml ),   \

NB An even better output organisation can be seen in piClim-histall/CM619-LR-piClim-histall-2 and -3  :
  2D radiation variables from 1st and 2nd call for TOA and SFC are output in "histmth"
  whereas the 3D and the *tropopose variables are output in a separate file "histmthForIRFtropo"
      that can be erased after producing TS_MO for all these variables in the post-processing. 

3/ 2D and 3D timeseria are made in postprocessing for all these variables needed to compute IRF at TOA, SRF and tropopause :
[Post_1M_histmth]
...
TimeSeriesVars2D= ... , rlutghg,rlutcsghg,rsutghg,rsutcsghg,  rsusghg,rsuscsghg,rsdsghg,rsdscsghg,rlusghg,rluscsghg,rldsghg,rldscsghg,    p_tropopause,t_tropopause,z_tropopause
TimeSeriesVars3D= ... , rsu,rsucs,rsd,rsdcs,rlu,rlucs,rld,rldcs,    rsughg,rsucsghg,rsdghg,rsdcsghg,rlughg,rlucsghg,rldghg,rldcsghg