bit for bit: with chemistry and with BAM only?

[mahowald@cornell_edu]

Hello!
I'm trying to see if I can get EXACTLY the same meteorology when running trop_chem or running only trop_bam, but I can't seem to do it, even if all my options are otherwise set to the same (and of course, chem_rad_passive               = .true.).  Is this because of something intrinsic in the model configuration that will change the climate when changing these options (and thus I can't do what I'm trying to do), or am I missing something in my set up or input files (and I should keep looking for it) .(I don't want the aerosols to be the same, necessarily, but the meteorology to be the same). I'm running F_2000, 1.9x1.9 compset otherwise. ThanksNatalie

 

[eaton]

I checked with Francis and we think this should work.  When I looked at the default namelists produced by a trop_mozart vs a trop_bam case it looked like it would be sufficient to customize the namelists by insuring that  the same initial file, ghg and prescribed bulk aerosols are used.  Setting chem_rad_passive=.true. resulted in the same rad_climate settings for the two cases, so as long as the prescribed radiative constiutents are the same then the runs should be the same.  One issue that was fixed in cam5_0_51 was to have build-namelist set atm_dep_flux=.false. when chem_rad_passive is true.  In an older version of cam (e.g. cesm1_0_x or older) you will need to set atm_dep_flux=.false. as part of the namelist customization. 

 

[mahowald]

Thanks very much Brian and Francis. My first tests with this suggest that this indeed going to help me solve the problem. It also turns out that if you remove the aer_wet_deplist from the namelist you can get the climate to not change, which my postdoc Dan Ward figured out (but doesn't help get us a full solution, of course, since we need wet dep of the aerosols!). Thanks!Natalie