prescribed_aero but not aerodep_flx ?

[drosa@lbl_gov]

Hi,if I prescribe aerosols but not aerosol fluxes in cam4, what's going to happen?Is the atm model going to calculate fluxes and pass them to the land model according to the prescribed aerosol concentration?What about the aerosol concentration? Will they be changed by the deposition flux calculation or will they be overridden by the
 prescribed amounts?Thank you!Daniele

 

[eaton]

In cam4 both the aerosol mixing ratios and the deposition fluxes are prescribed.  If you remove the prescription of the deposition fluxes I'm not sure what will happen, but I'll guess that some code which is responsible for putting the deposition fluxes into CAM's export state will fail.The code that calculates these fluxes is not active when aerosols are prescribed.  It is the calculation of wet and dry deposition by the prognostic aerosol code which produces the fluxes. 

 

[drosa@lbl_gov]

Thank you.Hmm, I guess I have to leave the prescribed deposition.Will it affect the prescribed concentration or are they completely independent? 

 

[eaton]

The prescribed aerosol mixing ratios are independent of the prescribed aerosol deposition.  If you want to turn off the aerosol deposition (whether it's prescribed or prognostic)  setting atm_dep_flux=.false. will do that. 

 

[drosa@lbl_gov]

Thank you.I keep having questions:
I prepared a file with SO4 and SO2 but it just read SO4:grep -i -e sulf -e so2 *
atm_in: prescribed_aero_specifier        = 'sulf:SO4', 'bcar1:CB1', 'bcar2:CB2', 'ocar1:OC1', 'ocar2:OC2', 'sslt1:SSLT01', 'sslt2:SSLT02',
atm_in:         'N:sulf:/project/projectdirs/ccsm1/inputdata/atm/cam/physprops/sulfate_camrt_c080918.nc', 'N:dust1:/project/projectdirs/ccsm1/inputdata/atm/cam/physprops/dust1_camrt_c080918.nc',

Is that expected?

 

[eaton]

The bulk model only has one sulfur bin (designated internally by 'sulf'), and the values are read from the variable 'SO4' as specified by prescribed_aero_specifier.  I don't know whether it's appropriate to combine SO2 and SO4 in that bin.  

 

[drosa@lbl_gov]

How does cb__c relate to prescribed aerosols?Example:cb_dust1_c:long_name = "dust1 column burden used in climate calculation"is different between 2 simulations where I prescribe the same dust concentration and the changes are in the amount of prescribed carbon and sulfate. I was not expecting this.I prescribed aerosol in this way:&prescribed_aero_nl
 prescribed_aero_datapath       = '/global/scratch2/sd/drosa/Data/Cesm-Inputdata/atm/cam/chem/trop_mozart_aero/aero'
 prescribed_aero_file       = 'aero_0.9x1.25_L26_CYC_MERRA.nc'
 prescribed_aero_specifier      = 'sulf:SO4', 'bcar1:CB1', 'bcar2:CB2', 'ocar1:OC1', 'ocar2:OC2', 'sslt1:SSLT01', 'sslt2:SSLT02',
         'sslt3:SSLT03', 'sslt4:SSLT04', 'dust1:DST01', 'dust2:DST02', 'dust3:DST03', 'dust4:DST04'
 prescribed_aero_type       = 'CYCLICAL'
/and for another simulation in a similar way.
For other 2 simulations where the carbon aerosol prescription is exactly the same (from the same input file) and the changes are in the cloud treatments, I still see difference in cb_ocar2_c, for example.

 

[wangh_11s@igsnrr_ac_cn]

Hi, I just want to change the aero concentration as well. I have changed the datapath, but after submit the case, the commends are revises to the initials, not what I have changed. Do you know why?Thank you!Huan