Scripts in this repository can be used to calculate/decompose the effective radiative forcing of anthropogenic aerosols (ERFaer). The method follows Ghan et al. (2013).
The decomposed forcing fields will be plotted in a multi-row figure with the net, shortwave (SW), and longwave (LW) forcing:
- Total ERFaer
- ERFaer due to aerosol-cloud interactions (ACI). This term includes indirect aerosol effect and semi-direct aerosol effect.
- ERFaer due to aerosol-radiation interactions (ARI). This is also often called direct aerosol effect.
- Clear-sky ARI
- Residual aerosol forcing (RES, including surface albedo effect, impact of water vapor, and Planck feedback)
More details can be found in Zhang et al. (2022).
Demo figures can be found at : https://github.com/kaizhangpnl/e3sm_erf_aerosol/tree/main/demo/E3SMv1_nudged_pdpi
The following figure shows the global distributions of decomposed net (left column), shortwave (middle column), and longwave (right column) effective aerosol forcing (∆F) at the top of model (TOM). The forcing is calculated based on a pair of nudged simulations with PD and PI aerosol/precursor emissions.
ALL indicates the total ∆F calculated from the difference between CTRL and E1850 (ALL=ARI+ACI+RES). ACI indicates the ∆F caused by aerosol-cloud interactions (2nd row), ARI the ∆F caused by aerosol-radiation interactions (3rd row), and RES (bottom row) the residual forcing. The clear-sky direct aerosol effect (4th row) is also shown. See Zhang et al. (2022) for details.
The following table shows the global and regional mean effective aerosol forcing at the top of model and at the surface.
The following setup works only for E3SMv1 and E3SMv2, with the updated MAM4 aerosol module (Wang et al. (2020)).
The namelist control needs to be added to user_nl_eam.
!!..................................................................
!! for aerosol forcing diagnsotics (decomposition)
!!
!! this will activate a second call to radiation without aerosols
!!..................................................................
rad_diag_1 = 'A:Q:H2O', 'N:O2:O2', 'N:CO2:CO2', 'A:O3:O3', 'N:N2O:N2O', 'N:CH4:CH4', 'N:CFC11:CFC11', 'N:CFC12:CFC12'
This is not for the forcing calculation, but would be useful for additional aerosol budget and optical property analysis.
!!..................................................................
!! for aerosol budget diagnostics, set the following the true
!!..................................................................
history_amwg = .true. !! default
history_aerosol = .true. !! for detailed mass budget analysis
history_aero_optics = .true. !! for detailed aerosol optical property analysis
history_verbose = .true. !! for detailed mass budget analysis (mass for individual modes)
!!..................................................................
!! for PD emission (2010) the first simulation
!!..................................................................
ext_frc_cycle_yr = 2010
ext_frc_specifier = 'SO2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so2_elev_1850-2014_c180205.nc',
'SOAG -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_soag_elev_1850-2014_c180205.nc',
'bc_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_bc_a4_elev_1850-2014_c180205.nc',
'num_a1 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a1_elev_1850-2014_c180205.nc',
'num_a2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a2_elev_1850-2014_c180205.nc',
'num_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a4_elev_1850-2014_c180205.nc',
'pom_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_pom_a4_elev_1850-2014_c180205.nc',
'so4_a1 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so4_a1_elev_1850-2014_c180205.nc',
'so4_a2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so4_a2_elev_1850-2014_c180205.nc'
ext_frc_type = 'CYCLICAL'
srf_emis_cycle_yr = 2010
srf_emis_specifier = 'DMS -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DMSflux.2010.1deg_latlon_conserv.POPmonthlyClimFromACES4BGC_c20190220.nc',
'SO2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so2_surf_1850-2014_c180205.nc',
'bc_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_bc_a4_surf_1850-2014_c180205.nc',
'num_a1 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a1_surf_1850-2014_c180205.nc',
'num_a2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a2_surf_1850-2014_c180205.nc',
'num_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a4_surf_1850-2014_c180205.nc',
'pom_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_pom_a4_surf_1850-2014_c180205.nc',
'so4_a1 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so4_a1_surf_1850-2014_c180205.nc',
'so4_a2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so4_a2_surf_1850-2014_c180205.nc'
srf_emis_type = 'CYCLICAL'
!!..................................................................
!! for PI emission (1850) the second simulation
!!
!! ext_frc_cycle_yr and srf_emis_cycle_yr should be changed
!!..................................................................
ext_frc_cycle_yr = 1850
ext_frc_specifier = 'SO2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so2_elev_1850-2014_c180205.nc',
'SOAG -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_soag_elev_1850-2014_c180205.nc',
'bc_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_bc_a4_elev_1850-2014_c180205.nc',
'num_a1 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a1_elev_1850-2014_c180205.nc',
'num_a2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a2_elev_1850-2014_c180205.nc',
'num_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a4_elev_1850-2014_c180205.nc',
'pom_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_pom_a4_elev_1850-2014_c180205.nc',
'so4_a1 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so4_a1_elev_1850-2014_c180205.nc',
'so4_a2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so4_a2_elev_1850-2014_c180205.nc'
ext_frc_type = 'CYCLICAL'
srf_emis_cycle_yr = 1850
srf_emis_specifier = 'DMS -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DMSflux.2010.1deg_latlon_conserv.POPmonthlyClimFromACES4BGC_c20190220.nc',
'SO2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so2_surf_1850-2014_c180205.nc',
'bc_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_bc_a4_surf_1850-2014_c180205.nc',
'num_a1 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a1_surf_1850-2014_c180205.nc',
'num_a2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a2_surf_1850-2014_c180205.nc',
'num_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_num_a4_surf_1850-2014_c180205.nc',
'pom_a4 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_pom_a4_surf_1850-2014_c180205.nc',
'so4_a1 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so4_a1_surf_1850-2014_c180205.nc',
'so4_a2 -> /compyfs/inputdata/atm/cam/chem/trop_mozart_aero/emis/DECK_ne30/cmip6_mam4_so4_a2_surf_1850-2014_c180205.nc'
srf_emis_type = 'CYCLICAL'
The main script is diag_aer_forcing.csh, which will use NCO and CDO to extract/merge/average the data and call the following NCL scripts to calculate/decompse the forcing:
- cal_erf_aer_time_mean_all.ncl (calculate/decompose forcing)
- make_table_erf_aer_ann_mean.ncl (create a summary table)
- plot_erf_aer_ann_mean_all.ncl (plot top-of-model (TOM) forcing)
- plot_erf_aer_ann_mean_all_surf.ncl (plot surface (SUR) forcing)
- plot_erf_aer_seas_mean.ncl (plot seasonal mean TOM forcing)
- NCO (https://nco.sourceforge.net/)
- CDO (https://code.mpimet.mpg.de/projects/cdo/)
- NCL (https://www.ncl.ucar.edu/)
- Ghan, S. J.: Technical Note: Estimating aerosol effects on cloud radiative forcing, Atmos. Chem. Phys., 13, 9971–9974, https://doi.org/10.5194/acp-13-9971-2013, 2013.
- Wang, H., Easter, R. C., Zhang, R., Ma, P.-L., Singh, B., Zhang, K., et al. (2020). Aerosols in the E3SM Version 1: New developments and their impacts on radiative forcing. Journal of Advances in Modeling Earth Systems, 12, e2019MS001851. https://doi.org/10.1029/2019MS001851
- Zhang, K. et al. Effective radiative forcing of anthropogenic aerosols in E3SM version 1: historical changes, causality, decomposition, and parameterization sensitivities, Atmos. Chem. Phys., 22, 9129–9160, https://doi.org/10.5194/acp-22-9129-2022, 2022.
Kai Zhang (kai.zhang@pnnl.gov)