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#2642 (possible bugs: salflx output unit and ln_rnf_icb has no effect) – NEMO

Opened 14 months ago

Closed 6 months ago

#2642 closed Bug (fixed)

possible bugs: salflx output unit and ln_rnf_icb has no effect

Reported by: mathiot Owned by: systeam
Priority: low Milestone:
Component: ICB Version: v4.0.*
Severity: minor Keywords: output, ICB,
Cc:

Description

Context

  • unit of the saltflx variable is in 1e-3/m2/s in field_def_oce.xml. I wonder if it should be instead in 1e-3.kg/m2/s as specified in the comments of ice.F90 for the variable sfx ?
  • I am not convince the icb climatology is used. icb climatology is read in sbcrnf in fwfisf, output as iceberg_cea or hflx_icb_cea (latent heat) but I am unable to find where this is added to rnf or emp in a forced simulation. If cpl, there is in sbccpl a line rnf = rnf + fwfisf. I did a try with ORCA2 and I have the same result whatever the value of ln_rnf_icb.
  • more general question/comments on ln_rnf_icb: I found confusing that the definition of the iceberg climatology is done in the runoff namelist instead of the icb namelist. A master flag ln_icb with ln_icb_clim for the use of the climatology and ln_icb_lagr for the use of the icb lagragian model is maybe more logical. This point could be discussed at the same time of the ticket #2467.

Analysis

It affect NEMO 4 and I didn't check the trunk.

Fix

point 1: If issue on saltflx confirmed, change in field_def_oce.xml is required.

point 2: add fwficb to rnf and add fwficb * rLfus to the runoff heat content flux.

Commit History (3)

ChangesetAuthorTimeChangeLog
14773clem2021-04-30T12:23:51+02:00

trunk: correct units of some icb diags (also related to ticket #2642)

14718clem2021-04-16T11:43:50+02:00

trunk: correctly handle diagnostics of mass, salt and heat budgets (see ticket #2652). And fix Pierre ticket #2642

14717clem2021-04-16T11:42:56+02:00

4.0-HEAD: correctly handle diagnostics of mass, salt and heat budgets (see ticket #2652). And fix Pierre ticket #2642

Change History (5)

comment:1 Changed 13 months ago by clem

I am currently checking this stuff for proper budgets and I agree with Pierre.

  • In coupled mode, iceberg mass flux is added to rnf in sbccpl.F90 and latent heat is added to qns.
  • In forced mode, iceberg mass flux is calculated in sbcrnf and outputed but never used. Same for latent heat.
  • saltflx is indeed in g(of salt)/m2/s while sfxice is in kg/m2/s. It is confusing.

=> These can be fixed relatively painlessly as Pierre suggested with the difference that I would suggest to put the latent heat of icebergs into qns as for coupled simulations (and not in hflx_rnf). Only sensible heat should be in hflx_rnf.

But I also have a couple of head scratching problems:

  • When icebergs are explicitely calculated (in ICB routines when ln_icebergs=T), things go really wild and I do not understand what's happening. Maybe the output berg_floating_melt is the equivalent of iceberg_cea but then what is calving? So, I will not touch any of this.
  • calving has a different meaning in coupled vs forced mode. In coupled mode this is the continental ice melt in the Northern Hemisphere. I am not sure it has any meaning in forced mode.
  • fwfisf has opposite sign compared to rnf. It is confusing and I suggest to change the sign except if it is done on purpose

comment:2 Changed 13 months ago by clem

In 14717:

Error: Failed to load processor CommitTicketReference
No macro or processor named 'CommitTicketReference' found

comment:3 Changed 13 months ago by clem

In 14718:

Error: Failed to load processor CommitTicketReference
No macro or processor named 'CommitTicketReference' found

comment:4 Changed 13 months ago by clem

In 14773:

Error: Failed to load processor CommitTicketReference
No macro or processor named 'CommitTicketReference' found

comment:5 Changed 6 months ago by mathiot

  • Resolution set to fixed
  • Status changed from new to closed

Thank you Clem for the fix in NEMO

The remaining general point mentioned has been moved to a specific ticket: #2740

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