Welcome to the new DiscussCESM forum!
We are still working on the website migration, so you may experience downtime during this process.

Existing users, please reset your password before logging in here: https://xenforo.cgd.ucar.edu/cesm/index.php?lost-password/

decrease aerosol emissions over a specific region

wxalpha

New Member
Hi all,

Thanks a lot for your reply and help in advance! I am conducting experiments to see how the changes in aerosol emissions drive the changes in regional climate. I want to reduce the aerosol emission by 20% over Asia.

I am not sure if it is correct to multiply every file in srf_emis_specifier by 0.8. Let's say for black carbon, the bc_a4 file is the surface emissions of black carbon. This has units of molecules/cm2/s. The num_a4 file is the particle number emissions file for the surface black carbon. This has units of (particles/cm2/s) * (molecules/mole) * (g/kg). Should I simply multiple both two files by 0.8?

I found a related thread https://bb.cgd.ucar.edu/cesm/threads/relationship-between-the-bc_a4-files-and-num_a4-file.4969/, but I am still confused about this.


Code:
&chem_inparm
chem_use_chemtrop        = .true.
clim_soilw_file        = '/glade/p/cesmdata/cseg/inputdata/atm/cam/chem/trop_mozart/dvel/clim_soilw.nc'
depvel_file        = '/glade/p/cesmdata/cseg/inputdata/atm/cam/chem/trop_mozart/dvel/depvel_monthly.nc'
depvel_lnd_file        = '/glade/p/cesmdata/cseg/inputdata/atm/cam/chem/trop_mozart/dvel/regrid_vegetation.nc'
exo_coldens_file        = '/glade/p/cesmdata/cseg/inputdata/atm/cam/chem/trop_mozart/phot/exo_coldens.nc'
ext_frc_specifier        = 'H2O ->  /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/elev/H2OemissionCH4oxidationx2_3D_L70_2014-2101_CMIP6-SSP5-8.5_c190307.nc',
         'num_a1 -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_num_so4_a1_anthro-ene_vertical_mol_175001-210101_0.9x1.25_c20190224.nc',
         'num_a1 -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/CMIP6_emissions_1750_2015/emissions-cmip6_num_a1_so4_contvolcano_vertical_850-5000_0.9x1.25_c20170724.nc',
         'num_a2 -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/CMIP6_emissions_1750_2015/emissions-cmip6_num_a2_so4_contvolcano_vertical_850-5000_0.9x1.25_c20170724.nc',
         'SO2    -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/CMIP6_emissions_1750_2015/emissions-cmip6_SO2_contvolcano_vertical_850-5000_0.9x1.25_c20170724.nc',
         'so4_a1 -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_so4_a1_anthro-ene_vertical_mol_175001-210101_0.9x1.25_c20190224.nc',
         'so4_a1 -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/CMIP6_emissions_1750_2015/emissions-cmip6_so4_a1_contvolcano_vertical_850-5000_0.9x1.25_c20170724.nc',
         'so4_a2 -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/CMIP6_emissions_1750_2015/emissions-cmip6_so4_a2_contvolcano_vertical_850-5000_0.9x1.25_c20170724.nc'
ext_frc_type        = 'INTERP_MISSING_MONTHS'
fstrat_list        = ' '
rsf_file        = '/glade/p/cesmdata/cseg/inputdata/atm/waccm/phot/RSF_GT200nm_v3.0_c080811.nc'
season_wes_file        = '/glade/p/cesmdata/cseg/inputdata/atm/cam/chem/trop_mozart/dvel/season_wes.nc'
srf_emis_specifier        = 'bc_a4    -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_bc_a4_anthro_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'bc_a4    -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_bc_a4_bb_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'DMS      -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_DMS_bb_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'DMS      -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-SSP_DMS_other_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'num_a1   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_num_so4_a1_bb_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'num_a1   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_num_so4_a1_anthro-ag-ship_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'num_a2   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_num_so4_a2_anthro-res_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'num_a4   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_num_bc_a4_bb_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'num_a4   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_num_bc_a4_anthro_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'num_a4   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_num_pom_a4_anthro_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'num_a4   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_num_pom_a4_bb_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'pom_a4   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_pom_a4_anthro_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'pom_a4   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_pom_a4_bb_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'SO2      -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_SO2_anthro-ag-ship-res_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'SO2      -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_SO2_anthro-ene_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'SO2      -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_SO2_bb_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'so4_a1   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_so4_a1_anthro-ag-ship_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'so4_a1   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_so4_a1_bb_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'so4_a2   -> /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_so4_a2_anthro-res_surface_mol_175001-210101_0.9x1.25_c20190224.nc',
         'SOAG ->   /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_SOAGx1.5_anthro_surface_mol_175001-210101_0.9x1.25_c20200403.nc',
         'SOAG ->  /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_SOAGx1.5_bb_surface_mol_175001-210101_0.9x1.25_c20200403.nc',
         'SOAG ->  /glade/p/cesmdata/cseg/inputdata/atm/cam/chem/emis/emissions_ssp585/emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_SOAGx1.5_biogenic_surface_mol_175001-210101_0.9x1.25_c20190226.nc'
srf_emis_type        = 'INTERP_MISSING_MONTHS'
tracer_cnst_datapath        = '/glade/p/cesmdata/cseg/inputdata/atm/cam/tracer_cnst'
tracer_cnst_file        = 'tracer_cnst_halons_3D_L70_2014-2101_CMIP6-SSP5-8.5_c190307.nc'
tracer_cnst_filelist        = ''
tracer_cnst_specifier        = 'O3','OH','NO3','HO2'
tracer_cnst_type        = 'INTERP_MISSING_MONTHS'
xactive_prates        = .false.
xs_long_file        = '/glade/p/cesmdata/cseg/inputdata/atm/waccm/phot/temp_prs_GT200nm_JPL10_c140624.nc'
 

andrew

Member
I think the best way to do this is to modify the emission files to your specifications.

If you want to reduce emissions over a region of Asia by 20%, then you could copy all the aerosol files, and write a script that multiplies all the variables you want (the files are for a species, and have different variables for different emissions sectors in them) by the 0.8 factor in a geographic region. Then you can point the namelist to the new files with the full path. This allows pretty infinite flexibility, but you do have to manage all the files.

Regards,

Andrew Gettelman
 

wxalpha

New Member
I think the best way to do this is to modify the emission files to your specifications.

If you want to reduce emissions over a region of Asia by 20%, then you could copy all the aerosol files, and write a script that multiplies all the variables you want (the files are for a species, and have different variables for different emissions sectors in them) by the 0.8 factor in a geographic region. Then you can point the namelist to the new files with the full path. This allows pretty infinite flexibility, but you do have to manage all the files.

Regards,

Andrew Gettelman
Hi Andrew,

Thank you so much for your help and reply! Your suggestions help a lot and I hope you do not mind I follow up your answer.

For instance, the anthropogenic surface black carbon emission is specified in
  1. bc_a4 -> emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_bc_a4_anthro_surface_mol_175001-210101_0.9x1.25_c20190224.nc
  2. num_a4 -> emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_num_bc_a4_anthro_surface_mol_175001-210101_0.9x1.25_c20190224.nc
In bc_a4, the unit is molecules/cm2/s. In num_a4, the unit is (particles/cm2/s) * (molecules/mole) * (g/kg). As these two files are both related to anthropogenic bc emission, I am wondering if they are somehow connected? Is it correct to multiply both files by 0.8 factor?

Thanks a lot,
Yujia
 

tilmes

Member
Hi Andrew,

Thank you so much for your help and reply! Your suggestions help a lot and I hope you do not mind I follow up your answer.

For instance, the anthropogenic surface black carbon emission is specified in
  1. bc_a4 -> emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_bc_a4_anthro_surface_mol_175001-210101_0.9x1.25_c20190224.nc
  2. num_a4 -> emissions-cmip6-ScenarioMIP_IAMC-REMIND-MAGPIE-ssp585-1-1_num_bc_a4_anthro_surface_mol_175001-210101_0.9x1.25_c20190224.nc
In bc_a4, the unit is molecules/cm2/s. In num_a4, the unit is (particles/cm2/s) * (molecules/mole) * (g/kg). As these two files are both related to anthropogenic bc emission, I am wondering if they are somehow connected? Is it correct to multiply both files by 0.8 factor?

Thanks a lot,
Yujia
[/QUOTE]
 

tilmes

Member
Hi Yujia,
it is correct to multiply both bc_a4 and num_a4 by 0.8 over the region of interest. num_bc_a4 is a product between the emissions (bc_a4 and other factors that are constant depending on the type of aerosol, as described in the post you pointed to. So a multiplication with the same fraction should do it.
Simone
 
Top