ismip7_forcing

The ismip7_forcing test group (compass.landice.tests.ismip7_forcing.Ismip7Forcing) processes (i.e., remaps and renames) the atmospheric and ocean thermal forcing data of the Ice Sheet Model Intercomparison for CMIP7 (ISMIP7) protocol from its native polar stereographic grid to the MALI unstructured mesh. The test group supports both AIS and GrIS via the ice_sheet config option. It includes two test cases: atmosphere and ocean_thermal.

framework

The shared config options for the ismip7_forcing test group are described in ismip7_forcing in the User’s Guide.

ice_sheet_params

The module compass.landice.tests.ismip7_forcing.ice_sheet_params defines a dictionary of ice-sheet-specific parameters (projection, file naming prefix, grid resolution, data version, ocean dimensionality) and provides the function compass.landice.tests.ismip7_forcing.ice_sheet_params.get_params() to retrieve them based on the ice_sheet config option.

configure

The module compass.landice.tests.ismip7_forcing.configure validates that all required config options in the [ismip7] section have been set by the user (i.e., are not NotAvailable).

create_mapfile

The module compass.landice.tests.ismip7_forcing.create_mapfile defines a unified framework for creating SCRIP and mapping files. The function compass.landice.tests.ismip7_forcing.create_mapfile.build_mapping_file() creates a SCRIP file from the input polar stereographic grid using the create_scrip_file_from_planar_rectangular_grid command from MPAS-Tools, then generates a mapping file via ESMF_RegridWeightGen. The projection is automatically determined from the ice_sheet config option using ice_sheet_params.

Test cases

atmosphere

The compass.landice.tests.ismip7_forcing.atmosphere.Atmosphere test case processes the ISMIP7 atmosphere forcing fields. It contains five steps: SMB, temperature, their respective gradients, and runoff. Each step discovers input files matching the ice-sheet-specific naming pattern, builds or reuses a mapping file, remaps each input file with ncremap, and combines/renames the results to MALI conventions.

Steps:

• ProcessSmb — acabf → sfcMassBal

• ProcessTemperature — ts → surfaceAirTemperature (clipped ≤ 273.15 K)

• ProcessSmbGradient — dacabfdz → sfcMassBalLapseRate

• ProcessTemperatureGradient — dtsdz → surfaceAirTemperatureLapseRate

• ProcessRunoff — mrro → ismip6Runoff

ocean_thermal

The compass.landice.tests.ismip7_forcing.ocean_thermal.OceanThermal test case processes the ISMIP7 ocean thermal forcing. It contains a single step, ProcessThermalForcing, which handles both AIS (3D, decade-spanning files) and GrIS (2D, yearly files) by branching on the ocean_3d parameter from ice_sheet_params.

For AIS, the step:

• Remaps thermal forcing preserving 30 vertical ocean layers

• Produces ismip6shelfMelt_3dThermalForcing (dims: Time × nCells × nISMIP6OceanLayers)

• Includes depth coordinate variables ismip6shelfMelt_zOcean and ismip6shelfMelt_zBndsOcean

For GrIS, the step:

• Remaps 2D monthly thermal forcing

• Produces ismip6_2dThermalForcing (dims: Time × nCells)