Topography Tasks

The e3sm/init/topo tasks create shared topography products and derived MPAS inputs that are reused by mesh-generation and E3SM initial-condition workflows.

Supported cubed-sphere products are:

  • ne3000

  • ne120

Supported latitude-longitude products are:

  • 1.00000_degree

  • 0.25000_degree

  • 0.12500_degree

  • 0.06250_degree

  • 0.03125_degree

Latitude-longitude product names follow the naming convention used by format_lat_lon_resolution_name(), which formats the resolution with 5 decimal places and appends _degree. For example, 0.125 becomes 0.12500_degree and 0.03125 becomes 0.03125_degree.

The standalone combine tasks listed below always regenerate the combined topography from scratch — they are not affected by the automatic caching that applies to downstream tasks. Other tasks that depend on a shared combine step (such as remap or ocean hydrography tasks) will automatically use cached outputs when they are available, without needing to opt in explicitly.

Standalone tasks are available to create each combined topography product:

  • e3sm/init/topo/combine_bedmap3_gebco2023/cubed_sphere/ne3000/task

  • e3sm/init/topo/combine_bedmap3_gebco2023/cubed_sphere/ne120/task

  • e3sm/init/topo/combine_bedmap3_gebco2023/lat_lon/1.00000_degree/task

  • e3sm/init/topo/combine_bedmap3_gebco2023/lat_lon/0.25000_degree/task

  • e3sm/init/topo/combine_bedmap3_gebco2023/lat_lon/0.12500_degree/task

  • e3sm/init/topo/combine_bedmap3_gebco2023/lat_lon/0.06250_degree/task

  • e3sm/init/topo/combine_bedmap3_gebco2023/lat_lon/0.03125_degree/task

The remap and cull tasks reuse these shared products when generating inputs for MPAS base meshes.

Remap and cull tasks are available for both simple (quasi-uniform and icosahedral) base meshes and for named unified meshes (see Unified base-mesh tasks). For a unified mesh named u.oi30.lr10, the task paths are:

  • e3sm/init/u.oi30.lr10/topo/remap

  • e3sm/init/u.oi30.lr10/topo/cull

The supported unified mesh names are the same as those listed in Unified base-mesh tasks.

Configuration Options

These tasks create shared config files in their work directories:

  • combine_topo.cfg for combine tasks

  • remap_topo.cfg for remap tasks

  • cull_topo.cfg for cull tasks

Combine Tasks

Combine tasks use the [combine_topo] section.

The following options are set automatically from the task path and normally should not be changed by hand:

  • target_grid

  • resolution_latlon

  • resolution_cubedsphere

Common user-tunable options are:

  • method: Remapping method used when combining datasets.

  • renorm_thresh: Threshold below which interpolated fields are not renormalized.

  • ntasks and min_tasks: Target and minimum MPI task counts for remapping.

  • latmin and latmax: Latitude range over which Antarctic and global topography are blended.

  • lat_tiles and lon_tiles: Tile counts used to decompose global remapping.

Visualization tasks also use viz_combine_topo_* sections for colormap and normalization settings.

Remap Tasks

Remap tasks use the shared [spherical_mesh] section together with [remap_topography].

Common user-tunable options are:

  • antarctic_boundary_convention: Antarctic coastline convention used to mask topography before remapping.

  • description: Metadata description written to the remapped product.

  • ntasks and min_tasks: Target and minimum MPI task counts for remapping.

  • renorm_threshold: Minimum land or ocean area fraction required before renormalizing elevation variables.

  • expand_distance and expand_factor: Smoothing controls for remapped topography.

For lower-resolution cubed-sphere source topography, Polaris automatically applies lower ntasks and min_tasks defaults from remap_low_res.cfg.

Visualization steps also use viz_remapped_topo_* sections for plot styling.

Cull Tasks

Cull tasks use the [cull_mesh] section.

Common user-tunable options are:

  • cpus_per_task and min_cpus_per_task: Thread-count settings for culling.

  • include_critical_transects: Whether critical land and ocean transects from geometric_features are enforced during masking.

  • sea_ice_latitude_threshold: Latitude poleward of which ocean transects are widened to avoid land-locked sea-ice cells.

  • land_locked_cell_iterations: Number of passes used to detect and remove land-locked ocean cells.

  • land_ice_max_latitude: Southern latitude threshold used to classify critical land transects as land ice.

  • land_ice_min_fraction: Minimum land-ice fraction used in south-pole flood filling for the land-ice mask.