[MITgcm-support] Simulation with varying atmospheric pCO2

[Charline Ragon]

Dear all,

I'm performing simulations in a coupled atmosphere, ocean and sea-ice 
configuration, using the biogeochemical packages GCHEM, DIC and PTRACERS.

I would like to allow a CO2-flux between atmosphere and ocean but I have 
troubles as all diagnostics are suddenly moving to zero (NaN are 
appearing in standard outputs). I set parameters dic_int1 = 3 and 
aim_select_pCO2 = 3, but if I change the value of aim_select_pCO2, this 
problem is not appearing (at least, I haven't observed it).

I had a look on, and attached to this e-mail, the evolution of 
atmospheric pCO2 in three similar simulations where I only change the 
aim_select_pCO2 value to 1, 2 or 3. These runs start from nIter0=0 and 
tracers are initialized by files. Note that, in my case aim_pCO2 = 
aim_ref_pCO2 = 320 ppm so it seems the absorption in CO2-band is 
constant and equals 4 also when aim_select_pCO2 = 1 (so, similar to 
aim_select_pCO2 = 0).

As I understand it, when the absorption in CO2-band is prescribed the 
simulation no exhibits the problem even if partial pressure of CO2 is 
largely increasing in both atmosphere and ocean. So, the zero-appearing 
should be related to this coefficient but I'm unable to understand 
exactly what the problem is nor to solve it.

I'm wondering if someone know more about this, and maybe have 
suggestions for me ?

Thanks in advance for your help!

Best,
Charline


--
Charline RAGON
PhD Student
Group of Applied Physics & Institute for Environmental Sciences
University of Geneva, Switzerland
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