DRYDEPVEL values all zero (with aer_drydep_opt = 1)

[Zuhayr Shahid]

Dear community members,

I hope this message finds you well. I have been trying to run WRF-Chem simulation over the western tropical South America to evaluate the impact of Black Carbon (BC) emitted from Amazon biomass burning and anthropogenic emissions on the melting of Andean glaciers. I have attached a sample figure of the output here: BC1 + BC2 (concentration at the surface in the units of micro-g/ kg of dry air). 

I would need to estimate dry deposition flux of BC. When I look into the variable "DRYDEPVEL" (dust dry deposition velocity) - I find all zeros. Below is the chem portion of my namelist (the full namelist is also attached, I am running with only one domain):

I wanted to kindly ask- if this is the correct variable to estimate dry deposition flux of BC? if yes, do I need to change chem_opt / other namelist settings/ registry.chem for valid outputs in the "DRYDEPVEL" variable? 

&chem
 kemit                               = 1
 chem_opt                            = 300, 300,
 chemdt                              = 10, 10,  
 emiss_opt                           = 6, 6,
 bio_emiss_opt      = 0,
 bioemdt                             = 30, 30,
 ne_area                             = 97,
 dust_opt      = 3,
 seas_opt      = 1,
 phot_opt                            = 0, 0,
 photdt                              = 0, 0,  
 aer_op_opt      = 1, 1,
 opt_pars_out      = 0,
 aer_ra_feedback      = 1, 1,
 chem_conv_tr      = 0, 0,
 biomass_burn_opt                    = 2, 2,
 scale_fire_emiss                    = .false., .false.,
 plumerisefire_frq                   = 30, 30,
 have_bcs_chem                       = .true., .false.,
 is_full_tuv                         = .false., .false.,
 has_o3_exo_coldens                  = .false.,
 aer_drydep_opt              = 1, 1,
 gas_drydep_opt                      = 0, 0,
 wetscav_onoff                       = 0, 0,  
 /

 I would really benefit a lot from any insights to this issue from the experts and scientists of the WRF-Chem community!

Best regards,

Zuhayr Ishmam

PhD student

Department of Atmospheric and Environmental Sciences

University at Albany, SUNY