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SOA in the CAM-Chem forecast data


New Member
I am driving my global model with CAM-Chem forecast data for the following species:
(/ 'H2O2 ', 'H2SO4 ', 'SO2 ', 'DMS ', &​
'SOAG ', 'so4_a1 ', 'pom_a1 ', 'soa_a1 ', &​
'bc_a1 ', 'dst_a1 ', 'ncl_a1 ', 'num_a1 ', 'so4_a2 ', &​
'soa_a2 ', 'ncl_a2 ', 'num_a2 ', &​
'dst_a3 ', 'ncl_a3 ', 'so4_a3 ', 'num_a3 ', &​
'pom_a4 ', 'bc_a4 ', 'num_a4 ' /)​
I have some queries pertaining to SOA species in the CAM-Chem forecast data.
  • The CAM-Chem forecast files include SOA for 5 categories (big-alkanes, -alkenes, toulene, isoprene and monoterpenes). However, I am not sure how to handle them. For example, the aerosol model requires the mixing ratios of soa in aitken and accumulation mode (soa_a2 and soa_a1). Do I need to simply add them all in their respective modes i.e., soa_a1[2] = soa1_a1[2] + soa2_a1[2] + soa3_a1[2] + soa4_a1[2] + soa5_a1[2]?
  • In addition, there is SOAG in the list. Fixed mass yields are given in Liu et al. (2012). Are mixing ratios for SOAG to be calculated similar to the above step, but with the multipliers given by Liu? VBS scheme is not being considered in my model yet.
  • The CAM-Chem forecast files does not include num_a4. How can it be calculated?