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WRF-CHEM aerosol initialization


New member
Hi,everyone. l'm using WRF-CHEM 4.1.4 whit CBMZ-MOSAIC_8BIN (chem_opt=10) to simulate aerosol concentration, but the result is not good. The simulation of surface PM2.5 and PM10 are 4-5 times higher than the observation. my wrfinput have bioemiss and anthro_emis, and it don’t have chemical data initial and boundary conditions using MOZBC.

l find the PM value in the first wrfout file is already very high. Meanwhile, it should be zero (because wrfinput don’t have chemical data initial and boundary conditions).
so l think my initialization setting maybe is wrong. l check my wrfinput files and find some gas species concentration are not zero (aerosol bins concentration are all zero), such as O3, NO.

my teacher advised me to use WRF-CHEM 3.9.1 and change the aer_ic_opt and aer_bc_opt from 1 to 16, but it didn't work (PM value is not zero still). then l found it worked if l changed chem_in_opt from 0 to 1. so l do the same setting in 4.1.4 to run real.exe, but encounter this bug.
” med_read_wrf_chem_input: Open file wrf_chem_input_d01”

l know why this bug come out. but l wonder
(1). why 3.9.1 can run successfully without wrf_chem_input files when using chem_in_opt=1, and 4.1.4 can’t. what’s the difference between two version?
(2). l only change chem_in_opt from 0 to 1 without any other change in 3.9.1. why chem_in_opt=1 can make PM value in the first wrfout file become zero ?
(3). what role do aer_ic_opt and aer_bc_opt and chem_in_opt play in aerosol initialization.
(4). does the setting ‘aer_ic_opt/ aer_ic_opt =16’ work in 3.9.1 and 4.1.4? l don’t find option 16 in user guide. it seems to exist in previous versions.

the following file is 3.9.1 namelist.input, which is same as that used in 4.1.


  • namelist.input
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