Version 7 (modified by laurent, 16 months ago) (diff)

More realistic air-ice/snow turbulent flux estimates over sea-ice

Last edition: 12/01/20 17:47:30 by laurent

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. Preview
  3. Tests
  4. Review


Action More realistic air-ice/snow turbulent flux estimates over sea-ice
PI(S) Laurent Brodeau @ Ocean Next
Digest Implementation of a bulk-transfer-coefficient parameterization for sea-ice-covered regions. This parameterization should consider sea-ice roughness and be able to handle extremely stable surface atmospheric layer conditions typical of sea-ice-covered regions.
Dependencies no
Branch source:/NEMO/branches/{YEAR}/dev_r{REV}_{ACTION_NAME}
Previewer(s) Names
Reviewer(s) Names
Ticket #2369


Describe the goal of development and the methodology,
add reference documents or publications if relevant.


Describe flow chart of the changes in the code.
List the Fortran modules and subroutines to be created/edited/deleted.
Detailed list of new variables to be defined (including namelists),
give for each the chosen name and description wrt coding rules.

Documentation updates

Using previous parts, define the main changes to be done in the NEMO literature (manuals, guide, web pages, …).


Since the preview step must be completed before the PI starts the coding, the previewer(s) answers are expected to be completed within the two weeks after the PI has sent the request to the previewer(s).
Then an iterative process should take place between PI and previewer(s) in order to find a consensus

Possible bottlenecks:

  • the methodology
  • the flowchart and list of routines to be changed
  • the new list of variables wrt coding rules
  • the summary of updates in literature

Once an agreement has been reached, preview is ended and the PI can start the development into his branch.


Once the development is done, the PI should complete the tests section below and after ask the reviewers to start their review.

This part should contain the detailed results of SETTE tests (restartability and reproducibility for each of the reference configuration) and detailed results of restartability and reproducibility when the option is activated on specified configurations used for this test

Regular checks:

  • Can this change be shown to produce expected impact (option activated)?
  • Can this change be shown to have a null impact (option not activated)?
  • Results of the required bit comparability tests been run: are there no differences when activating the development?
  • If some differences appear, is reason for the change valid/understood?
  • If some differences appear, is the impact as expected on model configurations?
  • Is this change expected to preserve all diagnostics?
  • If no, is reason for the change valid/understood?
  • Are there significant changes in run time/memory?

Test-cas associated with this development:

  • Test case functionality: test-case STATION_ASF checks that all bulk algorithms available in NEMO, used to estimate the bulk transfer coefficient for turbulent air-sea and air-ice fluxes, are working properly. This is done by checking that all turbulent fluxes computed at the punctual location of STATION_ASF lie within a reasonable range.
  • Test case setup: in STATION_ASF nemo.exe runs on one processor and needs only 2 lightweight netCDF files as input. These 2 files provide hourly time-series of sea-surface variables (SST, SSH), and surface atmospheric state (wind, temperature, humidity and downwelling radiative fluxes), respectively, at the punctual location of STATION_ASF. 1 year of simulation with STATION_ASF takes a few tens of seconds on 1 proc.
  • Test case verification value: WILL BE boolean. Each computed turbulent flux (hourly time-series), namely evaporation, wind stress and sensible flux, will be checked for consistency during a whole year. This operation will be carried out with every bulk (air-sea and air-ice) parameterization algorithms available in NEMO, including the testing of different options: cool-skin/warm-layer and wave-pattern input).
  • Status of the test case as for now: Exists on the official Git Hub? for NEMO. Boolean output not ready yet, version for air-ice fluxes in progress.


A successful review is needed to schedule the merge of this development into the future NEMO release during next Merge Party (usually in November).


  • Is the proposed methodology now implemented?
  • Are the code changes in agreement with the flowchart defined at preview step?
  • Are the code changes in agreement with list of routines and variables as proposed at preview step?
    If, not, are the discrepancies acceptable?
  • Is the in-line documentation accurate and sufficient?
  • Do the code changes comply with NEMO coding standards?
  • Is the development documented with sufficient details for others to understand the impact of the change?
  • Is the project literature (manual, guide, web, …) now updated or completed following the proposed summary in preview section?


Is the review fully successful? If not, please indicate what is still missing

Once review is successful, the development must be scheduled for merge during next Merge Party Meeting.