The ismip6_forcing test group (compass.landice.tests.ismip6_ forcing.Ismip6Forcing) processes (i.e., remapping and renaming) the atmospheric and oceanic forcing data of the Ice Sheet Model Intercomparison for CMIP6 (ISMIP6) protocol from its native polarstereo grid to the unstructure MALI mesh. The test group includes five test cases: atmosphere, ocean_basal, ocean_thermal_obs, ocean_thermal and shelf_collapse. The atmosphere test case has two steps: process_smb and process_smb_racmo; the ocean_basal and shelf_collpase test cases each have one step, process_basal_melt and process_shelf_collpase (respectively); the ocean_thermal_obs and ocean_thermal share one step, process_thermal_forcing. Each step has the local methods (functions) of remapping and renaming the original ISMIP6 data to the format that MALI can incorporate in its forward simulations. In remapping the data, all test cases import the method build_mapping_file to create or use scrip files of the source (ISMIP6) and destination (MALI) mesh depending on the existence of a mapping file. Below, we describe the shared framework for this test group and the 3 test cases.


The shared config options for the ismip6_forcing test group are described in ismip6_forcing in the User’s Guide.


The module compass.landice.tests.ismip6_forcing.create_mapfile defines a unified framework for creating the SCRIP and mapping files from the ISMIP6 source data files. The function compass.landice.tests.ismip6_forcing.create_mapfile.build_mapping_file() is the common interface to build the SCRIP files and mapping files. The scrip_from_latlon keyword argument is used to call the appropriate function for generating the SCRIP file. If scrip_from_latlon is false the command line executable from the MPAS_Tools conda package is used, otherwise the compass.landice.tests.ismip6_forcing.create_mapfile.create_scrip_from_latlon() function is used. Multiple methods for creating SCRIP files are necessary due to inconsistent dimensions names across the different ISMIP6 datasets.

Test cases


The compass.landice.tests.ismip6_forcing.atmosphere.Atmosphere performs processing of the surface mass balance (SMB) forcing. Processing data includes regridding the original ISMIP6 SMB data from its native polarstereo grid to MALI’s unstructured grid, renaming variables and correcting the SMB anomaly field for the MALI base SMB.


The compass.landice.tests.ismip6_forcing.ocean_basal.OceanBasal performs processing of the coefficients for the basal melt parameterization utilized by the ISMIP6 protocol. Processing data includes combining the IMBIE2 basin number file and parameterization coefficients and remapping onto the MALI mesh.


The compass.landice.tests.ismip6_forcing.ocean_thermal.OceanThermal performs the processing of ocean thermal forcing, both observational climatology (in ocean_thermal_obs) and the CMIP model data (in ocean_thermal). Processing data includes regridding the original ISMIP6 thermal forcing data from its native polarstereo grid to MALI’s unstructured grid and renaming variables.


The compass.landice.tests.ismip6_forcing.shelf_collapse.ShelfCollapse test case performs the processing of ice shelf collapse masks by remapping the original ISMIP6 forcing data to MALI’s unstructured grid and renaming variables.