MPAS-Dev/MPAS-Release: MPAS Version 6.0

This major release of MPAS introduces the MPAS-Seaice core, and it includes new functionality, general improvements, and fixes to the Ocean, Land Ice, and Atmosphere cores. Also included are various small improvements, optimizations, and clean-up in the shared software infrastructure. Specific changes to each of the MPAS components are detailed below.

Framework:

• Introduction of a new module for logging messages during model execution. Unless any errors are encountered, MPAS cores now write a single log file, named log.<core>.0000.out. In case errors occur, each MPI task will write its own error log file named log.<core>.<task ID>.err.
• Performance enhancements to aggregated halo exchanges used in the Ocean, Land-ice, and Sea-ice cores.
• Minor enhancements to the MPAS "stream manager", including the ability to specify "final_only" for the "input_interval" or "output_interval" of a stream to read/write that stream only at the model stop time.
• Various bug-fixes and other clean-up to ensure that the framework can be used in coupled-model configurations involving more than one MPAS core.

Atmosphere:

Relative to the v5.0 release, the MPAS v6.0 release represents a minor increment in capability for the MPAS-Atmosphere core. MPAS-Atmosphere v6.0 includes:

• An increase of the default number of layers from 41 to 55 to match the standard experimental set-up used at NCAR.
• The addition of support for the use of GMTED2010 terrain elevation, matching the default terrain dataset used in the WRF model.
  • Set config_topo_data = 'GMTED2010' in the namelist.init_atmosphere file when interpolating static fields.
• Computation of the GWDO sub-grid-scale orography fields in a way that is more consistent with the pre-computed fields used in the WRF model.
• Support for parallel builds of the init_atmosphere and atmosphere cores.
  • Use make -j N ....
• A significant reduction in the size of model initial conditions files.

Land Ice:

The last MPAS release with land ice improvements was v3.0. MPAS v6.0 adds the following significant features relative to v3.0:

• Adds support for the First-Order velocity solver through the external Albany library.
• Adds a thermal solver that can be solved in terms of temperature (verified) or enthalpy (experimental).
• Adds subglacial hydrology model.
• Adds a number of calving options including eigencalving.
• Adds an adaptive time stepper.
• Adds analysis members for global and regional statistics.
• Ability to couple with E3SM.
• Adds a number of test cases and model configurations.
• General cleanup and bug fixes.

Ocean:

• Ability to couple with E3SM.
• New in-situ analysis computations.
• Division of tracers into groups to control output, algorithms, and forcing.
• Addition of biogeochemistry tracers and column computations.

Sea Ice:

• First release of MPAS-Seaice.
• MPAS-Seaice solves the sea-ice momentum equation with an Elastic-Viscous-Plastic rheology and variational horizontal operators adapted for the MPAS mesh.
• Horizontal transport of mass and tracers uses an incremental remapping scheme.
• Column physics and biogeochemistry uses an early version of the Icepack library.