ACCESS-OM3 fun run missing diagnostics

COSIMA
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1

Hi, I had some time in my hands and ran a few days of om3 25km (https://github.com/ACCESS-NRI/access-om3-configs/tree/dev-MC_25km_jra_iaf). I modified my diag_table using the data_table_source file, but some of the diagnostics I requested were not outputted. The diagnostics were: salt_left_behind, heat_added, heat_content_massin, heat_content_massout`.All of these diagnostics were listed in the available_diags.0000 file.

This is an example bit of my diag_table

# SURFACE FLUXES DIAGNOSTICS 2D HOURLY

"access-om3.mom6.2d.salt_left_behind.3hr.mean.%4yr", 3, "hours", 1, "days", "time", 1, "years"
"ocean_model", "salt_left_behind", "salt_left_behind", "access-om3.mom6.2d.salt_left_behind.3hr.mean.%4yr", "all", "average", "none", 2

"access-om3.mom6.2d.salt_flux_added.3hr.mean.%4yr", 3, "hours", 1, "days", "time", 1, "years"
"ocean_model", "salt_flux_added", "salt_flux_added", "access-om3.mom6.2d.salt_flux_added.3hr.mean.%4yr", "all", "average", "none", 2

"access-om3.mom6.2d.salt_flux_in.3hr.mean.%4yr", 3, "hours", 1, "days", "time", 1, "years"
"ocean_model", "salt_flux_in", "salt_flux_in", "access-om3.mom6.2d.salt_flux_in.3hr.mean.%4yr", "all", "average", "none", 2

"access-om3.mom6.2d.salt_flux.3hr.mean.%4yr", 3, "hours", 1, "days", "time", 1, "years"
"ocean_model", "salt_flux", "salt_flux", "access-om3.mom6.2d.salt_flux.3hr.mean.%4yr", "all", "average", "none", 2

Does anyone know why this is happening?

Please let me know if I need to provide any other contextual information.

3

@JuliaN Sorry, we just spotted your topic. @dougiesquire will look into it. You’ll probably need to wait until tomorrow for a reply, though.

4

Hi @JuliaN,

The TLDR is that these four diagnostic fields are never actually allocated in MOM6 in ACCESS-OM3 which leads to the confusing behaviour that they appear in the available_diags.0000 file despite not actually being available.

The reasons they are not allocated are:

  • salt_left_behind is based on a coupled field that is not (currently) coupled when using NUOPC (the salt left behind by brine rejection). The diagnostic is only available when using the FMS coupler.
  • heat_added is only available if restoring surface temperature or using the flux adjustment functionality to adjust the heat flux. Are you doing either of these things?
  • heat_content_massin and heat_content_massout are not available in ACCESS-OM3 because we use the MOM6 parameter ENTHALPY_FROM_COUPLER=.true., meaning the heat contents of mass fluxes are received from the coupler rather than diagnosed by MOM6. You may find the following diagnostics useful. These are the heat contents received from the coupler.
    • heat_content_lrunoff
    • heat_content_frunoff
    • heat_content_lprec
    • heat_content_fprec
    • heat_content_evap
    • heat_content_cond

I agree it’s very confusing that the available_diags.0000 file suggests these are available. Thanks for reporting. I think fixing this would require some fairly widespread changes to MOM6, but we’ll see what we can do.

5

Ok that makes sense thanks @dougiesquire ! I’ll keep this in mind :slight_smile: