Increase methane concentration

[deepashree_dutta@student_unsw_edu_au]

Hi all,

I've quadrupled methane concentration in WACCM4 by changing the lower boundary condition in flbc_file. ('~/CESM/inputdata/atm/waccm/lb/LBC_1765-2005_1.9x2.5_CMIP5_za_c091204.nc').
I've changed both variables CH4_LBC and CH4_LBC_mean in flbc_file and made necessary changes in user_nl_cam pointing to the new file.
Is it the correct way of increasing methane concentration in the model?

When I check the output variables I can see large increase in methane concentration.
But, the changes in water vapor mixing ratio in the lower stratosphere is very small which seems suspicious to me.

Thank you!
Deepashree

 

[mmills]

The change you implemented at the lower boundary will take many simulated years to propagate upward to the stratosphere. If you want more immediate results, you can also quadruple CH4 in your initial condition.