kangerlussuaq

The landice/kangerlussuaq test group includes a test case for creating a mesh for Kangerlussuaq Glacier, Greenland. The optimization for basal friction happens outside of COMPASS because it requires expert usage and takes a larger amount of computing resources than COMPASS is typically run with.

The test group includes a single test case that creates the variable resolution mesh.

config options

The test group uses the following default config options. At this point only the mesh generation options are adjusted through the config file.

[mesh]

# number of levels in the mesh
levels = 10

# distance from ice margin to cull (km).
# Set to a value <= 0 if you do not want
# to cull based on distance from margin.
cull_distance = 5.0

# mesh density parameters
# minimum cell spacing (meters)
min_spac = 1.e3
# maximum cell spacing (meters)
max_spac = 1.e4
# log10 of max speed (m/yr) for cell spacing
high_log_speed = 2.5
# log10 of min speed (m/yr) for cell spacing
low_log_speed = 0.75
# distance at which cell spacing = max_spac (meters)
high_dist = 1.e5
# distance within which cell spacing = min_spac (meters)
low_dist = 1.e4

# mesh density functions
use_speed = True
use_dist_to_grounding_line = False
use_dist_to_edge = True

# Whether to interpolate data (controls run_optional_interpolation)
interpolate_data = False
# path to directory containing BedMachine and Measures datasets
# (default value is for Perlmutter)
data_path = /global/cfs/cdirs/fanssie/standard_datasets/GIS_datasets/

# geojson used to create the cull mask in mesh generation
geojson_filename = greenland_only_outline_45km_buffer_latlon_singlepart.geojson

# filename of the BedMachine thickness and bedTopography dataset
# (default value is for Perlmutter)
bedmachine_filename = BedMachineGreenland-v6_edits_floodFill_extrap.nc

# filename of the MEaSUREs ice velocity dataset
# (default value is for Perlmutter)
measures_filename = greenland_vel_mosaic500_extrap.nc

# projection of the source datasets, according to the dictionary keys
# create_scrip_file_from_planar_rectangular_grid from MPAS_Tools
src_proj = gis-gimp

# number of processors to use for ESMF_RegridWeightGen
nProcs = 128

mesh_gen

landice/kangerlussuaq/default creates a variable resolution mesh. The default is 1-10km resolution with mesh density determined by observed ice speed and distance to ice margin. There is no model integration step.

If optional BedMachine and/or MEaSUREs datasets are configured, they are subset to the mesh bounding box from [mesh] before SCRIP generation and conservative remapping to reduce memory and runtime. The base-mesh projection used in build_mali_mesh() is fixed for this test case.