Draft of release notes for FESOM2.1 release.

[koldunovn]

Changes in development

• moved to GitHib for development.
• meshes under version control now (https://gitlab.awi.de/fesom)
• Simple tests (compile, run, compare results) for GitHub repository (on every commit). First implementations is in Add GitHub action to do sanity check on gfortran Ubuntu #4.
• Updated documentation (https://fesom2.readthedocs.io/en/latest/)

Major changes

• Parallel and asynchronous output writing (parallel and asynchronous output writing #14).
• Added Icepack sea ice thermodynamics (Zampieri et al., 2021) Icepack merge #70
• Added backscatter parameterisation (Juricke et al., 2019) Backscatter #64
• Initial version of cavities (Workbench merge cavity #48)
• New defaults in the namelists and a system to create setups from yaml files (Workbench partcell #55). Most prominent changes are: Partial cells, zstar and unrotated mesh are now default options, JRA55-do is default forcing.
• New license (LGPL), as requested by some partners, so FESOM2 can be used as a library by comertial software New license #74
• Add an option to smooth tracer (smooth_bh_tra), which is nessesary for very high resolution setups A new option in namelist.oce -> smooth_bh_tra. A tracer biharmonic di… #81
• Fix partial cells to work more stable in high resolution setups Workbench fixpartcell #27

Minor changes

• Print compile time git SHA at runtime (Version info #13) to undetify version the model was compiled with.
• More information in netCDF output ([WIP] More information in netCDF output #18 add mesh checksum to output files #31 prefix the global NetCDF attributes so they do not conflict with attr… #33). Provide some info on model version and setup.
• Fix bug with partitioner, that sometimes lead to wrong size of triangles Cyclicity #20
• Add several extra parameters to the sea ice namelist (Add parameters to the namelist.ice #34)
• Introduce MAX_PATH length, to remove limit on the paths introduce MAX_PATH length #65
• Ice deformation tensor is stored as an array (on elements) and can bу written out (4cfe296)
• Remove old METIS4 (66b0b74)
• Add cray ftn compiler support ([WIP] use the right interface, explicit interface was already set #89)
• Fix coupled (to OpenIFS) thermodynamics where water instead of snow density was used for heat capacity (Awicm3 ice thermo cpl fixes #93)

References

Juricke, S., Danilov, S., Kutsenko, A., & Oliver, M. (2019). Ocean kinetic energy backscatter parametrizations on unstructured grids: Impact on mesoscale turbulence in a channel. Ocean Modelling, 138, 51–67. https://doi.org/10.1016/j.ocemod.2019.03.009

Zampieri, Lorenzo, Frank Kauker, Jörg Fröhle, Hiroshi Sumata, Elizabeth C. Hunke, and Helge Goessling. Impact of Sea-Ice Model Complexity on the Performance of an Unstructured-Mesh Sea-ice/ocean Model Under Different Atmospheric Forcings. Washington: American Geophysical Union, 2020. https://dx.doi.org/10.1002/essoar.10505308.1.