[MITgcm-support] Total carbon calculation in a fully-coupled configuration

[Zhu, Fangze]

Dear all,

I am working on a fully-coupled configuration with an interactive carbon cycle. To do so, I set the parameter “aim_select_pCO2=3” in the file data.aimphys (attached).

The problem is that the total carbon I calculated have almost linear decreasing trends, and different experiments have different decreasing rates. The figure is also attached. I would expect some numerical noise but there should not be any trends in this figure.

My approach to calculate total carbon inventory in the model is:

Total carbon = atmospheric carbon + total DIC + organic carbon
Specifically,
atmospheric carbon = pCO2 * 1E-6 * total_atmos_moles
where pCO2 is taken from “aim_pCO2_ave” in pCO2StDiag.*, in ppm, and “total_atmos_moles” is 1.77E20.
total DIC = DIC * ocean volume
where DIC is diagnosed from “TRAC01_ave” in BioStDiag.*, in mol C/m^3, and ocean volume is from “TRAC01_vol” in BioStDiag.*, in m^3.
organic carbon = R_cp * DOP * ocean volume
where R_cp = 117, and DOP is taken from “TRAC04_ave” in BioStDiag.*, in mol P/m^3.

Did I do it wrong? Are there any carbon sinks that I have not been aware of?

Thank you so much in advance!

Best,
Fangze

-------------------------------------------------------------------------
Fangze Zhu
PhD student | Teaching Assistant
Department of Atmospheric & Environmental Sciences
University at Albany, SUNY
Office: ES 309
fzhu at albany.edu<mailto:fzhu at albany.edu>

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