iHAMOCC: Bugfix for sediment alkalinity needed? about blom HOT 10 CLOSED

I agree with your analysis. Some time ago we changed rnit -> (rnit+1) and corrected (hopefully) the stochiometry of denitrification in ocprod, but these changes were never carried over into the sediment code. So it would be excellent to change this.

This should go into the beyond-CMIP6 branch (the sediment code was switched on in CMIP6, so these changes will break backwards bit-for-bit reproducibility).

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Hi @JorgSchwinger , ok, thanks for the swift response! Then I am going to prepare a branch and pull request (both based on beyond-CMIP6) for this the next days.

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Hi @JorgSchwinger and @TomasTorsvik , I added sulf13,14 to the code to reflect the code changes done for 12C. However, now I stumbled over the stoichiometric values in the denitrification part of powach.F90 again, when looking at the NO3 consumption and N2 production. To my understanding, these values need to be changed as well:

For NO3: 98 -> rdnit1 (which is 121.6)
and for N2: 57 -> rdnit2 (which is 68.8 = 121.6/2+16/2, energy requirement and POM degradation)
Further, when calculating posol, we need to divide by 2.*rdnit2 instead of 114 (=2*57).

I'll add this and would merge it, if you agree.

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@JorgSchwinger and @TomasTorsvik , I am a bit puzzled about these lines -only present- in aerobic remin and denitrification

 ! is this correct? no corresponance in the lines above
 powtra(i,j,k,ipowc13) = powtra(i,j,k,ipowc13) + poso13*umfa
 powtra(i,j,k,ipowc14) = powtra(i,j,k,ipowc14) + poso14*umfa

To my understanding, the powtra are updated twice due to these lines, since in l. 543-550, part Calculate updated degradation rate from updated undersaturation, the 13,14C are again updated via the aerobic13,14 and anaerobic13,14 fields. I would therefore suggest to delete these lines for aerobic remin and denitrification.

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@JorgSchwinger and @TomasTorsvik , in general, I feel it would be good to merge master into the beyond-CMIP6 branch either before (then I will handle merge conflicts) or directly after (then somebody else or me handles the merge conflicts) due to the recent sediment porosity implementations in master. I think that after these changes, the isotope code should be up-to-date in the sediment.

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in general, I feel it would be good to merge master into the beyond-CMIP6 branch either before (then I will handle merge conflicts) or directly after (then somebody else or me handles the merge conflicts) due to the recent sediment porosity implementations in master.

I agree with this. I tend to think that it is better to merge master to beyond-CMIP6 before merging in a new code change. This way you can resolve potential conflicts between master and the old beyond-CMIP6 in a separate step (hopefully there should not be any), before creating a new beyond-CMIP6. If you do it the other way around, it may be more difficult to untangle if a conflict with master is due to the old beyond-CMIP6 or the new code changes. It's a minor point, either way should work I guess.

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Thanks for taking care this, Jöran. The sediment isotope code was never really finished (the model has not been tested with C-isotopes and sediments switched on). So it is well possible that there are still errors (i.e. I would agree deleting the lines of code mentioned above).

Regarding the stochiometry, I did the update of the water-column part with help of Iris (Kriest), so I hope the water column part is correct. If the sediment is inconsistent with this, would be great to fix this (I can't really judge the details right now without diving deeper into the code - I trust your suggestions are correct).

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@JorgSchwinger and @TomasTorsvik , I made the code changes and would now be ready to merge with the beyond-CMIP6 branch. I just spoke to Tomas, who will merge master into the feature branch before I do the merge, since I know from a local test that it will result in merge conflicts.

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After merging the master into beyond-CMIP6 branch, I resolved any conflicts and the bug-fixing branch is ready to be merged into beyond-CMIP6.

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Merged.

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