Opened 6 months ago

Closed 4 weeks ago

#2376 closed Defect (fixed)

Incorrect restart after the first year of the model run when option 2 of the freshwater-budget adjustment mechanism is active (`nn_fwb = 2`, module `sbcfwb`)

Reported by: smueller Owned by: smueller
Priority: low Milestone:
Component: SBC Version: 4.0-HEAD
Severity: minor Keywords: fwb
Cc:

Description

Context

Output from the model in a variant of the ORCA2_ICE_PISCES reference configuration (OCE without icebergs, ICE unchanged, TOP excluded) exhibits unexpected, apparently unphysical features following a restart after several years of the model run.

Analysis

A test of the restartability at the first model restart failed. Further analysis revealed that upon model restarts, the freshwater-budget adjustment option selected in reference configuration ORCA2_ICE_PISCES (nn_fwb = 2, module sbcfwb) causes the adjustment flux to be read in from file EMPave_old.dat (thus, it is set to the value used during the first year of the model run) rather than to be set to the value appropriate for the previous year of simulation (as it is in continuous model runs).

Recommendation

The freshwater-budget adjustment flux from the previous year should be stored in and recovered from restart files if nn_fwb is set to 2.

Commit History (1)

ChangesetAuthorTimeChangeLog
13280smueller2020-07-09T13:53:42+02:00

Remedy for the defect described in ticket #2376

This modification comprises the merging of changesets [12591] and [12602] made in branch /NEMO/branches/2020/ticket2377 as a remedy for the corresponding defect in the trunk version of NEMO (see ticket #2377).

Change History (7)

comment:1 Changed 5 months ago by smueller

  • Owner changed from systeam to smueller
  • Status changed from new to assigned

comment:2 Changed 5 months ago by smueller

When nn_fwb = 2, the restartability of model runs longer than one year can be achieved by copying the content of file EMPave.dat produced by the preceding model-run segment to file EMPave_old.dat prior to the model restart. While these two files are described in subection 6.13.6 of the manual for the most recent release version of NEMO, the appropriate restart procedure for option 2 of the freshwater adjustment mechanism is not. To avoid incorrect model restarts as a result of the omission of copying or renaming the EMPave.dat file, the restart capability of this option should be normalised.

comment:3 Changed 4 months ago by clevy

  • Version changed from release-4.0 to release-4.0-HEAD

comment:4 Changed 4 months ago by clevy

  • Version changed from release-4.0-HEAD to 4.0-HEAD

comment:5 Changed 4 weeks ago by smueller

As outlined in comment:5:ticket:2377, the lack of standard restart capability for option 2 of the freshwater-budget adjustment mechanism can be demonstrated using a modified version of the SETTE ORCA2_ICE_PISCES restartability test run over 11680 timesteps with a restart after 8760 timesteps. Such a test is unsuccessful (both using the default restart option and after activating XIOS-based restart with ln_xios_read = .TRUE. and nn_wxios = 1) when carried out for source:/NEMO/releases/r4.0/r4.0-HEAD@13274.

The merging of changesets [12591] and [12602] from branch source:/NEMO/branches/2020/ticket2377 (see ticket #2377) into source:/NEMO/releases/r4.0/r4.0-HEAD@13274 normalises the restart capability for this option. With this modification, the 11680-timestep variant of the ORCA2_ICE_PISCES restartability test is successful (both using the default restart option and XIOS-based restart); further, all standard SETTE tests are successful (no change of the compared output files with respect to source:/NEMO/releases/r4.0/r4.0-HEAD@13274).

comment:6 Changed 4 weeks ago by smueller

In 13280:

Remedy for the defect described in ticket #2376

This modification comprises the merging of changesets [12591] and [12602] made in branch /NEMO/branches/2020/ticket2377 as a remedy for the corresponding defect in the trunk version of NEMO (see ticket #2377).

comment:7 Changed 4 weeks ago by smueller

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

source:/NEMO/releases/r4.0/r4.0-HEAD@13280 has passed the standard SETTE tests.

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