Set the total column of a density profile. The column is integrated between the user-defined altitude and TOA (top of atmosphere). The syntax is  

mol_modify species column unit

 
where species is one of O3, O2, H2O, CO2, NO2, BRO, OCLO, HCHO, O4, SO2, CH4, N2O, CO, or N2, see also mol_file. The second argument is the total column value, and the third argument is the unit, in which the column is given. The unit can be DU (Dobson units), CM_2 (molecules/cm{}^{2}) or MM.

Please note that the unit MM is only valid for species H2O and specifies the precipitable water in kg / m2 (which is approximately 1mm).The water vapor profile is scaled accordingly. The precipitable water is integrated from the user-defined altitude to TOA (top of atmosphere).

The default units are DU for O3, and CM_2 for all other gases. It is possible to have several mol_modify commands in the input file (maximum one per species). The following sets the NO{}_{2} total column to 1.2 DU.  

mol_modify NO2 1.2 DU