To add the double radiation call to the simulation (no matter what time period you run), you have to add a couple changes.
First, looking at this line (or similar) in you namelist: "CaseDocs/atm_in" this part shows what gases and aerosols will be included in the first or normal radiation call (it may look slightly different in the version you are using).
rad_climate = 'A:Q:H2O', 'A:O2:O2', 'A:CO2:CO2',
'A:O3:O3', 'A:N2O:N2O', 'A:CH4:CH4',
'N:CFC11STAR:CFC11', 'A:CFC12:CFC12', 'M:mam3_mode1:/glade/p/cesmdata/cseg/inputdata/atm/cam/physprops/
mam4_mode1_rrtmg_aeronetdust_sig1.6_dgnh.48_c140304.nc',
'M:mam3_mode2:/glade/p/cesmdata/cseg/inputdata/atm/cam/physprops/
mam4_mode2_rrtmg_aitkendust_c141106.nc', 'M:mam3_mode3:/glade/p/cesmdata/cseg/inputdata/atm/cam/physprops/
mam4_mode3_rrtmg_aeronetdust_sig1.2_dgnl.40_c150219.nc'
To get a second radiation call (double radiation call in the model), you can define what this should include in for example doing this:
rad_diag_1 = 'A:Q:H2O', 'A:O2:O2', 'A:CO2:CO2', 'A:O3:O3', 'A:N2O:N2O', 'A:CH4:CH4', 'N:CFC11STAR:CFC11',
'A:CFC12:CFC12'
With this, your second radiation call only includes gases and no aerosols, so you have removed the radiation part from the 3 modal aerosol modes..
(You have to add this to the user_nl_cam file).
To write out the variables that comes out of the second calculation, you just add these additional variables to the namelist
'FLDS_d1', 'FLNSC_d1', 'FLNS_d1', 'FLNTC_d1', 'FLNT_d1',
'FLUTC_d1', 'FLUT_d1', 'FSDSC_d1', 'FSDS_d1', 'FSNSC_d1', 'FSNS_d1', 'FSNTC_d1', 'FSNTOAC_d1',
'FSNTOA_d1', 'FSNT_d1', 'FSUTOA_d1', 'LWCF_d1', 'QRL_d1', 'QRS_d1', 'SOLIN_d1', 'SWCF_d1',
