CO2 concenteration-driven historical compset wrongly set ocean CO2 boundary

[tjiputra]

Describe the bug
In concentration-driven historical compset the field
<entry id="OCN_CO2_TYPE" value="constant">

is wrong, and should be 'diagnostic' instead of 'constant'

Alternatively, i think this can be solved by using the following compset instead:

HIST_CAM70%LT%NORESM%CAMoslo_CLM60%FATES-NOCOMP_CICE_BLOM%HYB%ECO_MOSART_DGLC%NOEVOLVE_SWAV_SESP_BGC%BDRD

• NorESM version:
  NorESM3

• HPC platform:

• Compiler (if applicable):

• • Compset (if applicable):
    HIST_CAM70%LT%NORESM%CAMoslo_CLM60%FATES-NOCOMP_CICE_BLOM%HYB%ECO_MOSART_DGLC%NOEVOLVE_SWAV_SESP

• Resolution (if applicable):

• Error message (if applicable):

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Expected behavior
A clear and concise description of what you expected to happen.

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Additional context
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[TomasTorsvik]

@tjiputra - I'm a bit confused by this bug issue.
As far as I know, and also looking at the file NorESM/cime_config/config_compsets.xml (in the noresm3_0_beta12a tag), we have not defined any compset alias for the concentration-driven historical compset. At least, I have only used the "long name" format for all runs with NorESM3.

[tjiputra]

@TomasTorsvik , i just want to point out that the long name compset for the concentration-driven historical run should be:
HIST_CAM70%LT%NORESM%CAMoslo_CLM60%FATES-NOCOMP_CICE_BLOM%HYB%ECO_MOSART_DGLC%NOEVOLVE_SWAV_SESP_BGC%BDRD

otherwise, the atmospheric CO2 read by the ocean is wrong. A future reference.

Perhaps this shouldn't be tagged as bug(?). I'll remove the bug tag.

[mvertens]

@tjiputra @TomasTorsvik - OCN_CO2_TYPE is set in the blom config_component.xml according to the following:

  <entry id="OCN_CO2_TYPE">
    <type>char</type>
    <valid_values>constant,prognostic,diagnostic</valid_values>
    <default_value>constant</default_value>
    <values>
      <value compset="_BLOM.*%ECO"           >constant</value>
      <value compset="_BLOM.*%ECO.*_BGC%BPRP">prognostic</value>
      <value compset="_BLOM.*%ECO.*_BGC%BDRD">diagnostic</value>
      <value compset="_DATM%CPLHIST.*_BLOM.*%ECO">constant</value>
      <value compset="20TR_DATM%IAF.*_BLOM.*%ECO">diagnostic</value>
    </values>
    <group>run_component_blom</group>
    <file>env_run.xml</file>
    <desc>Determines provenance of atmospheric CO2 for gas flux computation.
      This option is used in the BLOM ecosystem model.
      The default is constant.</desc>
  </entry>

You do not want to add a _BGC%BDRD to the compset definition - instead you want to change the BLOM config_component.xml to have the following:
<value compset="_CAM">diagnostic</value>
This is consistent with how MOM6 is handling this in CESM and current historical simulations in CESM that are concentration driven do not have the _BGC%BDRD suffix. @matsbn @JorgSchwinger - do you agree with this?

[JorgSchwinger]

@mvertens How would this logic then distinguish between concentration-driven and emission-driven compsets? "_CAM" can't be enough, since it is present in both?

[mvertens]

@JorgSchwinger - if you look at the full list for MOM6:

<entry id="OCN_CO2_TYPE">
   <type>char</type>
   <valid_values>constant,prognostic,diagnostic</valid_values>
   <default_value>constant</default_value>
   <values>
     <value compset="_CAM">diagnostic</value>
     <value compset="_MOM6%[^_]*MARBL-BIO.*_BGC%BPRP">prognostic</value>
     <value compset="_MOM6%[^_]*MARBL-BIO.*_BGC%BDRD">diagnostic</value>
     <value compset="_DATM%CPLHIST.*_MOM6%[^_]*MARBL-BIO">diagnostic</value>
     <value compset="^OMIP_DATM%IAF.*_MOM6%[^_]*MARBL-BIO">diagnostic</value>
     <value compset="^OMIP_DATM%JRA.*_MOM6%[^_]*MARBL-BIO">diagnostic</value>
   </values>
   <group>run_component_mom</group>
   <file>env_run.xml</file>
   <desc>Determines provenance of atmospheric CO2 for gas flux computation.
     This option is used in MARBL.
     The default is constant.</desc>
 </entry>

you see that BGC%BPRP and _BGC%BDRD" override the CAM setting.

If you look at what _BGC%BPRP and _BGC%BDRD do - they set the CCSM_BGC mediator xml variable that determines the following:

 <entry id="CCSM_BGC">
    <type>char</type>
    <valid_values>none,CO2A,CO2B,CO2C</valid_values>
    <default_value>none</default_value>
    <values match="last">
      <value compset="_CAM">CO2A</value>
      <value compset="_DATM">none</value>
      <value compset="_DATM%CPLHIST.+BLOM%ECO">CO2A</value>
      <value compset="^OMIP_DATM%IAF.*_MOM6%[^_]*MARBL">CO2A</value>
      <value compset="^OMIP_DATM%JRA.*_MOM6%[^_]*MARBL">CO2A</value>
      <value compset="HIST.*_DATM.*_CLM">CO2A</value>
      <value compset="SSP.*_DATM.*_CLM">CO2A</value>
      <value compset="_BGC%BPRP">CO2C</value>
      <value compset="_BGC%BDRD">CO2C</value>
      <value compset="20TR_DATM%IAF.*_BLOM%ECO">CO2A</value>
      <value compset="20TR_DATM%JRA.*_BLOM%ECO">CO2A</value>
    </values>
    <group>run_coupling</group>
    <file>env_run.xml</file>
    <desc>Activates additional CO2-related fields to be exchanged between components. Possible values are:
    CO2A: sets the driver namelist variable flds_co2a = .true.; this adds
    prognostic CO2 and diagnostic CO2 at the lowest model level to be sent from
    the atmosphere to the land and ocean.

    CO2B: sets the driver namelist variable flds_co2b = .true.; this adds
    prognostic CO2 and diagnostic CO2 at the lowest model level to be sent from
    the atmosphere just to the land, and the surface upward flux of CO2 to be
    sent from the land back to the atmosphere

    CO2C: sets the driver namelist variable flds_co2c = .true.; this adds
    prognostic CO2 and diagnostic CO2 at the lowest model level to be sent from
    the atmosphere to the land and ocean, and the surface upward flux of CO2
    to be sent from the land and the open ocean back to the atmosphere.

    The namelist variables flds_co2a, flds_co2b and flds_co2c are in the
    namelist group cpl_flds_inparm.
    </desc>
  </entry>

So concentration driven scenarios would use CO2A - but in turn, BLOM needs to set the OCN_CO2_TYPE to be diagnostic when running with CAM in a concentration driven run. Does this help clarify things?

[JorgSchwinger]

@tjiputra after talking to @mvertens , I have provided a (preliminary) fix here: NorESMhub/BLOM#722

Note that the logic with _BGC%BPRP and _BGC%BDRD does NOT work since both options set CCSM_BGC=CO2C. We will have to look further into the definition of compsets, but NorESMhub/BLOM#722 should provide a possibility to run concentration-driven historical. For emission-driven, you have to append _BGC%BPRP to the compset name (as a temporary fix)

[mvertens]

@JorgSchwinger - after examining the code in more detail - both _BGC%BPRP and _BGC%BDRD turn on emission driven scenarios. However, for _BGC%BDRD - the prognostic CO2 in CAM is not radiatively active. I'm not sure BGC%BPRP is a temporary fix. But we can discuss this in more detail at the compset hackathon.