How to calculate so4_a1 and so4_a2?

[Renfxuan]

I want to replace the default SO2 emission with my own SO2 emissions in F2000climo. The sulfate emis = SO2_emis * 0.025. What are the proportions of so4_a1 and so4_a2 in the total sulfate emissions, respectively?
I really need the help.

 

[rrbuchholz]

Hi Ren,
You will need to also reduce the amount of SO2 by the amount of so4 you create. Below is a snippet of code from how I create so4 for fire emissions (it all goes into so4_a4 for fires because there is no so4_a2 from fires).
Hope that helps!
Best,
Rebecca

;------------------------------------------------
if (tracer.eq."SO4") then
diam = 0.134e-06
rho_SO4 = 1770.
mw = 115. ; CAM-chem reads SO4 as NH4HSO4 in MAM (mw_so4 for BAM is 96)
end if

;********************************************
; SO4 created from SO2
; Also create num_* species
if (tracer.eq."SO4") then

emiss_so2_new = 0.975 * emiss_in
emiss_so4 = 0.025 * emiss_in
mass_particle = rho_SO4 *(PI/6.) *(diam)^3 ;mass per particle (kg/particle)
; CESM scales emissions by amufac when read in
; (to convert molec/cm2/s to kg/m2/s)
; amufac = 1.65979e-23 = (1E-3kg/g)*(1E4cm2/m2)/Avog
; therefore number emissions files are also scaled by 1/amufac
num_emiss = emiss_so4 * mw /mass_particle ;(particles/cm2/s)(molecules/mole)(g/kg)


; to write out
new_names = (/"SO2", "so4_a1", "num_so4_a1"/)
new_emiss = (/emiss_so2_new, emiss_so4, num_emiss/)
end if

end if

 

[Renfxuan]

Hi Ren,
You will need to also reduce the amount of SO2 by the amount of so4 you create. Below is a snippet of code from how I create so4 for fire emissions (it all goes into so4_a4 for fires because there is no so4_a2 from fires).
Hope that helps!
Best,
Rebecca

;------------------------------------------------
if (tracer.eq."SO4") then
diam = 0.134e-06
rho_SO4 = 1770.
mw = 115. ; CAM-chem reads SO4 as NH4HSO4 in MAM (mw_so4 for BAM is 96)
end if

;********************************************
; SO4 created from SO2
; Also create num_* species
if (tracer.eq."SO4") then

emiss_so2_new = 0.975 * emiss_in
emiss_so4 = 0.025 * emiss_in
mass_particle = rho_SO4 *(PI/6.) *(diam)^3 ;mass per particle (kg/particle)
; CESM scales emissions by amufac when read in
; (to convert molec/cm2/s to kg/m2/s)
; amufac = 1.65979e-23 = (1E-3kg/g)*(1E4cm2/m2)/Avog
; therefore number emissions files are also scaled by 1/amufac
num_emiss = emiss_so4 * mw /mass_particle ;(particles/cm2/s)(molecules/mole)(g/kg)


; to write out
new_names = (/"SO2", "so4_a1", "num_so4_a1"/)
new_emiss = (/emiss_so2_new, emiss_so4, num_emiss/)
end if

end if

Thanks so much. It helps me a lot!