Plans for BLOM/iHAMOCC for NorESM3.0

[TomasTorsvik]

Tentative plans for default (and optional) settings for BLOM/iHAMOCC towards NorESM3.0

When shall MCT support phase out?
Due to changes in the timing of releases of NorESM2.3 and NorESM2.5, fixes in the hybrid coordinates would be good to enter a tag 1.8 of Blom that still supports MCT and could still be used together with NorESM2.3. See also: #439
(jmaerz: I suggest to mark those items here as bold)

BLOM-specific

• only mks (default) (remove cgs dependencies)
• Test all model configurations with NUOPC coupler
• Apply existing higher order vertical reconstruction for the remapping of diagnostic fields on to reference depths (hybrid coord. only, reconstruction does not exist for isopycnic coord.)
• Make pre-defined sets of output size, e.g. blom_outvol = small/medium/large simplified output choices for BLOM #252
• fix negative tracers in hybrid coordinates due to virtual freshwater fluxes

iHAMOCC-specific

• Reconsider output for Hamocc kwrbioz off - enable remin and primary prod throughout full water column #367 & to make it default (+ remove the old split) - see Removing process separation between euphotic and deep ocean regions in iHAMOCC? #399
• Cold start of preformed (silicate) tracer - handle all preformed tracers equally - refer to Initialization of preformed tracers #356 for the provision of climatologies of preformed tracers. Clean-up of restart option for preformed silicate (currently checks, if prefsilicate is present, which could be removed) (Would be good in tag 1.8 with MCT)
• Remove/modify compsets for the extended N cycle (in cime_config/config_component.xml)
• Potentially enable to include weathering rates
• Nitrogen cycling interactive coupling through NUOPC?
• New DOC code (first) as optional
• Write output for rivers and any interpolated input fields introduced by Mariana
• Write output for limiting nutrient
• Boundary conditions: CDEPS versus MCT based, see ndep forcing file is incorrect for most compsets using DATM #411, time coordinates and file for dust deposition are incorrect for new stream functionality #404, Preparing N-deposition input files for CMIP6 scenarios and historical runs #397, iHAMOCC support for tnx0.5v1 grid #376 (How shall we best proceed with this? - shall we aim at a consistent set of MCT-compatible forcing files? - also for 0.5degree? - jmaerz started with it for N-deposition, but stopped due to the CDEPS developments - I can continue working on it, if needed)