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2018WP/VALID-12_CLEVY_CoupledInterface – NEMO
wiki:2018WP/VALID-12_CLEVY_CoupledInterface

Version 17 (modified by clevy, 4 years ago) (diff)

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VALID-12_CLEVY_CoupledInterface

The PI is responsible to closely follow the progress of the action, and especially to contact NEMO project manager if the delay on preview (or review) are longer than the 2 weeks expected.

  1. Summary
  2. Abstract
  3. Implementation
  4. Reference manual and web pages updates
  5. Preview
  6. Tests
  7. Review

Summary

Action VALID-12_CLEVY_CoupledInterface
PI(S) C. Levy

Digest

Validation of NEMO coupled interface, using OASIS in the trunk (as future 4.0 release)

Dependencies
Expected for
Ticket #2147
Branch NEMO/branches/$YEAR/dev_r{REV}_{ACTION_NAME}
Previewer(s) S. Masson, R. Hill, E. Maisonnave
Reviewer(s) S. Masson, R. Hill, E. Maisonnave
Link ExtractUrl(.)?

Abstract

The NEMO OASIS interface is important for all coupled configurations. Testing that this section (mainly the coupling activated) is functional must be done before the 4.0 announcement.

Implementation

To check if the coupling interfaces are functional, three steps/tests will be set up:

STEP1: Validation of the SAS reference configuration

STEP2: Set up a test using NEMO (starting from the global reference configuration) with key_coupled, OASIS active and a toy atmospheric model

STEP3: Using this configuration, check that the coupled interface is functional for ocean dynamics, sea ice and biogeochemistry

Reference manual and web pages updates

Not done yet

Preview

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

For this taks, no development is scheduled: the goal is only to check that the coupling interface of NEMO 4.0 is working.
The advice of previewer on the list of proposed tests is of course welcome.

Tests

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

TEST1: Validation of the SAS reference configuration

The reference configuration ORCA2_SAS_LIM has run sucessfully for 1 year using the set up defined in the NEMO shared reference (NEMO trunk rev 10272).
It has been compared with a one year run of the forced reference configuration ORCA2_ICE_PISCES (NEMO trunk rev 10272).
Validation of the results:

  • Some questions raised on the forced configuration itself, see below
  • After one year experiment, the ice restart file is created in the SAS run and looks like a correct ice restart file
  • Having a complete an exact validation of this configuration will need some more work: here the ice is forced with an ocean input file containing the surface fields. These fields are not varying with time for now in the input file. To have a complete validation, it would need:
    • to run a one year of ORCA2_ICE_PISCES full reference configuration, with outputs of these daily surface fields
    • to use this output as input to the SAS configuration
    • to make some subtle changes in SAS in order to have the exact same use of these fields in time (not the case for now, work done once by Sébastien and Eric, remaining to be taken in account again
    • Once all this is done, the ice restart file should be strictly identical between the ORCA2_ICE_PISCES run and the ORCA2_SAS_LIM one

This work has not been done at this stage, so that for now the conclusion is:
The ORCA2_SAS_LIM configuration is running in NEMO 4.0, e.g. the SAS interface is functionnal in this case.

Comments on forced reference configuration ORCA2_ICE_PISCES :
The reference configuration is set up to start from rest (e.g. the very initial start, no ocean restart at all). In this case, using a call frequency of the ice =3 , nn_fsbc=3, is unstable: the run crashes after a few tenth of timesteps. Using nn_fsbc=5 (e.g. ice called every 5 timesteps, inducing less high frequencies in the forcing since the mean value used is calculated on a longer time scale), the model runs fine. This instabilities was not expected in the ORCA2 configuration, usually considered as very stable. Still this nn_fsbc=5 values has always been used up to now...
Once the ocean has started, after a few years, it seems that the nn_fsbc=3 option is indeed stable enough.

TEST2: Set up a test using NEMO (starting from the global reference configuration) with key_coupled, OASIS active and a toy atmospheric model

Using this configuration, check that the coupled interface is functional for ocean dynamics, sea ice and biogeochemistry

  • OASIS3-MCT version is installed, revision xxx
  • a CPL_TOYATM configuration is created, based on ORCA2_ICE_PISCES, and with oasis cpp keys key_oasis3 key_oa3mct_v3 active is created
  • First compilation problem, requests a fix in oasis for now (see attached file in the ticket #2147 )
  • The toyatm developped by Eric Maisonnave is compiled as a simple toy for the atmosphere
  • iodef.xml modified for OASIS use
  • the number of (fake) fields is adjusted in the namcouple and namelist_cfg files
  • Coupling frqequence is set to 1 (every time steps)
  • Test is short (5 timesteps, since the atmspheric fields are constant in space and time and not realistic)
  • The run is completed

Validation: the NETCDF file of SST seen by the toy atmosphere looks reasonable.

The global 2° configuration in a very simple coupled mode using OASIS is running fine with NEMO 4.0, e.g. the OASIS interface between ocean dynamics, sea ice and atmosphere is functionnal.

Summary

As a result of the tests, a few things needs to be updated/fixed:

  • sbccpl.F90
  • namelist_ref

A new test case has been build with a toy for the atmosphere (proposed name for this new test case: YAZD, for Yardstick Atmosphere to Zero a Demonstrator, since yazd is an oasis in Iran...). It is proposed to add this configuration in the list of available test cases.

Review

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

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