Feature Masks

The ocean/feature_masks/configurable task creates standard MPAS mask files on an existing native ocean mesh. It uses the same [feature_masks] options as the mesh-component feature-mask task, including mesh_filename, mesh_name, and mask_group; see Feature Masks for the common mask behavior and output conventions.

This ocean task is the place to use Omega-format mesh input. The step opens the mesh through the ocean component’s model I/O layer, so Omega variable and dimension names are translated back to standard MPAS-Ocean names before mask creation. For Omega, mesh dimensions in the mask output, such as NCells and NEdges, are mapped back to native names. Region and transect dimensions and mask variables keep their MPAS names, since Omega does not yet define names for them.

Use the mesh-component task instead when the input file is already a standard MPAS mesh and no ocean-model-specific I/O translation is needed.

MOC Basins

When mask_group = MOC Basins, the step performs an extra post-processing pass after the normal region-mask computation. mpas_tools.ocean.moc.add_moc_southern_boundary_transects is called with the basin cell masks and the mesh dataset to derive southern-boundary transect masks for each MOC basin; these are appended to the output dataset alongside the region masks.

The output file is named {mesh_name}_mocBasinsAndTransects{date}.nc (instead of the normal {mesh_name}_mocBasins{date}.nc) so downstream tools such as MPAS-Analysis can locate the combined file.

Example

polaris setup -t ocean/feature_masks/configurable -w ocean_feature_masks

Edit ocean_feature_masks/ocean/feature_masks/configurable/feature_masks.cfg to point at the mesh file and select the mask group, then run the task. Missing required options are reported when the task runs, after the work-dir config has been edited.