Plans for BLOM/iHAMOCC for NorESM2.5

[TomasTorsvik]

Tentative plans for default (and optional) settings for BLOM/iHAMOCC towards NorESM2.5
See also #438

• We will keep the MCT support until the technical release of NorESM2.5 (Plans for MCT support in upcoming BLOM/iHAMOCC versions #439)

• cgs units support will phase out - likely keep unit support for the restart files reading to enable restart from former restart files

• Plans for further development have been moved to a new overview issue: Plans for BLOM/iHAMOCC for NorESM3.0 #462

Planning for release-1.7

Tasks under this heading can go into a new release-1.7, and will be carried forward into NorESM2.5.

BLOM-specific

• BLOM code refactorization
• hybrid coordinates (default) (isopycnal optional)
• Add 2 degree grid resolution
• Add 1/2 degree grid resolution
• Fix some blom tnx2v1 namelist parameters Fix some namelist parameters for tnx2v1 grid #463
• support git fleximod git fleximod support for submodules in BLOM (?) #465 and add git fleximod support to .gitmodules #466

iHAMOCC-specific

• (potentially) making output files more cdo-compatible Add lon,lat info in iHAMOCC output to more comply to cdo commands  #355
• Potentially remove separation of processes into euphotic and non-euphotic zone processes - refer to Enable primary production beyond current kwrbioz and enable POC remin above #365 and Hamocc kwrbioz off - enable remin and primary prod throughout full water column #367
• Make preformed tracers optional - to enable switching them off for HR runs - done via Making preformed tracers optional to enable HR runs without them #394
• Remove the option to run cyanobacteria (bluefix) in the MLD (default remains to run them in the euphotic zone) - see Remove MLD switch for cyanobacteria - making euphotic zone N2 uptake remaining default  #395 and Remain with cyanobacteria only in euphotic zone. #396
• bugfix sediment extended N-cycle Bugfix DNRA and introduce max_limiter #413
• dust flux to sediment output Dust fluxes output and add descriptions in the xml-namelist file #420
• Unify N-deposition reading - done with always obtain ndep from datm or cam using cmeps/cdeps #410 (for nuopc) - see Preparing N-deposition input files for CMIP6 scenarios and historical runs #397 and Unify N-deposition input reading #398 for some further discussion. For post- BLOM tag v1.6.x simulations, nuopc is expected to handle the input, while for tag v1.6.x simulations with the extended nitrogen cycle switched on, a limited set of input files are generated by @jmaerz (request in case of interest)
• Make i) T-dep. and ii) O2-dep. of remineralization available to default model code via thus far optional switch- see Step-wise introduction of T-dep. and O2-dep of remineralization? #400 and Introduce switch dor T- and O2-dependent remineralization #424 , where the first step with a switch is taken for the water column - sediment thus far missing (only realized for the extended N cycle) - Temperature- and O2-dependent sediment remineralization #454
• Add time attributes to be cdo/xr-conform #449
• New tag for M4AGO Update M4AGO scheme to version v1.1.1 (equivalent to dev-1.1.1) #460
• Update POC remin rate in sediment Correct POC remineralization rate #461 and Increase value of sediment POC degradation constant #464

[TomasTorsvik]

This should maybe go into the milestone description at some point. Just edit the first entry if you have more things to add.

[mvertens]

@TomasTorsvik @matsbn @JorgSchwinger @jmaerz - some of these tasks will no longer be needed once we use the new stream functionality in BLOM. In particular you will not need separate datasets for 2 degree and 1/2 degree. I hope to start implementing this next week. We had decided to move ahead with the 1/2 degree using the older approach since simulations were going to being very soon and we did not want the new implementation holding up the science. However, I hope to have this in place so that we don't need to generate new datasets for 2 degrees and then hopefully move all the resolutions to just interpolation from the original source. At least that is what I think that @matsbn was leaning towards.

[TomasTorsvik]

The release for NorESM2.5 has been pushed forward, so v1.7.0 will now be the intended release tag for NorESM2.5.