Hello! I used CESM2.1.3 to run a BSSP370cmip6 compset case with resolution of f09_g17. I tried different ways to simulate local surface iron fertilization in the Bcase.
Firstly, I tried to add a new iron source in POP by referring to fe_sediment or fe_river flux. The implementation of local iron fertilization requires three steps, I think. Step 1, I need to create a new .nc input data file for this new source like fe_sediment or fe_river flux, and apply values in local areas (such as the Southern Ocean) in this new .nc file. Step 2, add the pathway for this new .nc file in the namelist_defaults_pop.xml and namelist_definition_pop.xml. Last but not least, step 3, I need to make sure this new iron source is calculated in the formation of iron concentration. I think I have done Step 1 and 2 correctly before.
However, I failed to find how these different iron sources finally shape the distribution of iron concentration. So if I have created a new iron source input data file (new_fe_source.nc, e.g.) by referring to fe_river flux (which is read from /ocn/pop/gx1v7/forcing/riv_nut.gnews_gnm.gx1v7_nn_open_ocean_nnsm_e1000r300_marginal_sea.201
70425.nc). My question is that, is it feasible to conduct local surface iron fertilization experiments by adding a new iron source here? If yes, how to apply this new iron source to the calculation of iron concentration in POP? If not, are there other better ways?
I initially thought that there was a formula like fe_flux_total = fe_sediment_flux + fe_vent_flux + fe_river_flux + fe_atm_flux, so that I could just add a new source behind the code (like fe_flux_total = fe_sediment_flux + ... + fe_new_flux). But I found POP did not work like that. It seemed that the possible process of calculating total iron flux might be in the POP file ecosys_forcing_mod.F90 line 775, I thought,
case ('Iron Flux')
if (trim(iron_flux_source).eq.'driver-derived') then
bc_dep_ind = n
call surface_flux_forcings(n)%add_forcing_field(field_source='internal', &
marbl_varname=marbl_varname, field_units=units, &
driver_varname='BLACK_CARBON_FLUX', rank=2, id=n)
else if (trim(iron_flux_source).eq.'monthly-calendar') then
Fe_dep_ind = n
file_details => iron_flux_file_loc
call init_monthly_surface_flux_forcing_metadata(file_details)
call surface_flux_forcings(n)%add_forcing_field( &
field_source='POP monthly calendar', &
marbl_varname=marbl_varname, field_units=units, &
forcing_calendar_name=file_details, rank=2, id=n)
else
write(err_msg, "(A,1X,A)") trim(iron_flux_source), &
'is not a valid option for iron_flux_source'
call document(subname, err_msg)
call exit_POP(sigAbort, 'Stopping in ' // subname)
end if
But I failed to understand how to add my new iron source here.
As these questions have confused me for days, I am truly appreciate any insights and suggestions. Thank you!
Best regards
Firstly, I tried to add a new iron source in POP by referring to fe_sediment or fe_river flux. The implementation of local iron fertilization requires three steps, I think. Step 1, I need to create a new .nc input data file for this new source like fe_sediment or fe_river flux, and apply values in local areas (such as the Southern Ocean) in this new .nc file. Step 2, add the pathway for this new .nc file in the namelist_defaults_pop.xml and namelist_definition_pop.xml. Last but not least, step 3, I need to make sure this new iron source is calculated in the formation of iron concentration. I think I have done Step 1 and 2 correctly before.
However, I failed to find how these different iron sources finally shape the distribution of iron concentration. So if I have created a new iron source input data file (new_fe_source.nc, e.g.) by referring to fe_river flux (which is read from /ocn/pop/gx1v7/forcing/riv_nut.gnews_gnm.gx1v7_nn_open_ocean_nnsm_e1000r300_marginal_sea.201
70425.nc). My question is that, is it feasible to conduct local surface iron fertilization experiments by adding a new iron source here? If yes, how to apply this new iron source to the calculation of iron concentration in POP? If not, are there other better ways?
I initially thought that there was a formula like fe_flux_total = fe_sediment_flux + fe_vent_flux + fe_river_flux + fe_atm_flux, so that I could just add a new source behind the code (like fe_flux_total = fe_sediment_flux + ... + fe_new_flux). But I found POP did not work like that. It seemed that the possible process of calculating total iron flux might be in the POP file ecosys_forcing_mod.F90 line 775, I thought,
case ('Iron Flux')
if (trim(iron_flux_source).eq.'driver-derived') then
bc_dep_ind = n
call surface_flux_forcings(n)%add_forcing_field(field_source='internal', &
marbl_varname=marbl_varname, field_units=units, &
driver_varname='BLACK_CARBON_FLUX', rank=2, id=n)
else if (trim(iron_flux_source).eq.'monthly-calendar') then
Fe_dep_ind = n
file_details => iron_flux_file_loc
call init_monthly_surface_flux_forcing_metadata(file_details)
call surface_flux_forcings(n)%add_forcing_field( &
field_source='POP monthly calendar', &
marbl_varname=marbl_varname, field_units=units, &
forcing_calendar_name=file_details, rank=2, id=n)
else
write(err_msg, "(A,1X,A)") trim(iron_flux_source), &
'is not a valid option for iron_flux_source'
call document(subname, err_msg)
call exit_POP(sigAbort, 'Stopping in ' // subname)
end if
But I failed to understand how to add my new iron source here.
As these questions have confused me for days, I am truly appreciate any insights and suggestions. Thank you!
Best regards