How to change ozone concentration

[deepashree_dutta@student_unsw_edu_au]

Hi all,

I am trying to run WACCM with CAM5 physics and I have two simple questions:

1. I created two cases using F_2000_WACCM5 and a user defined compset for 1850. For both cases the partial ozone and oxygen column density is the same (exo_coldens_file- /inputdata/atm/cam/chem/trop_mozart/phot/exo_coldens.nc).
Why do these compsets use the same exo_coldens_file (considering different ozone concentrations in the atmosphere)?
Is the model prescribed with the same ozone and oxygen column density every year (since I see 12 time steps)?

2. I want to reduce ozone concentration in my experiment. How to do this?
(I can see ozone as one of the variables in initial condition files in both cases. Do I simply change the O3 variable in ncdata?)

Thanks a lot,
Deepashree

 

[mmills]

The exo_coldens_file only includes O2 and 03 column densities above the model top (~145 km) for look-up-table photolysis. See:

CESM2 CAM6.3 Namelist Definitions

Namelist definitions for CAM6.3 in CESM2

www.cesm.ucar.edu

Ozone is calculated in WACCM, not prescribed. Therefore, you cannot reduce the ozone between the surface and the model top in WACCM. If you want to run with prescribed ozone, you can use a specified chemistry WACCM (SC-WACCM) compset, or CAM. Because WACCM with CAM5 physics is not an official version of the model, you may not find SC-WACCM5 compsets appropriate to your experiments.

Is there a reason why your experiment needs to be done with WACCM with CAM5 physics rather than WACCM6, CAM5, CAM6, or WACCM4, all of which are supported versions?

 

[deepashree_dutta@student_unsw_edu_au]

Thanks Mike!
I'll try to use WACCM4/WACCM6 instead of CAM5.