crane

The landice/crane test group includes a test case for creating a mesh for Crane Glacier, Antarctica. 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.

# config options for mesh_gen test case
[mesh]

# number of levels in the mesh
levels = 10

# Bounds of Crane regional mesh
x_min = -2.442e6
x_max = -2.246e6
y_min = 1.124e6
y_max = 1.334e6

# 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 = -1.0

# mesh density parameters
# minimum cell spacing (meters)
min_spac = 5.e2
# maximum cell spacing (meters)
max_spac = 1.e3
# log10 of max speed for cell spacing
high_log_speed = 2.5
# log10 of min speed for cell spacing
low_log_speed = 0.75
# distance at which cell spacing = max_spac
high_dist = 1.e5
# distance within which cell spacing = min_spac
low_dist = 5.e4

# mesh density parameters used if use_bed = True
# These settings are taken from the Humboldt mesh
# and have not yet been evaluated for Crane.
# distance at which bed topography has no effect
high_dist_bed = 1.e5
# distance within which bed topography has maximum effect
low_dist_bed = 5.e4
# Bed elev beneath which cell spacing is minimized
low_bed = 50.0
# Bed elev above which cell spacing is maximized
high_bed = 100.0

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

# 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/AIS_datasets

# filename of the BedMachine thickness and bedTopography dataset
# (default value is for Perlmutter)
bedmachine_filename = BedMachineAntarctica_2020-07-15_v02_edits_floodFill_extrap_fillVostok.nc

# filename of the MEASURES ice velocity dataset
# (default value is for Perlmutter)
measures_filename = antarctica_ice_velocity_450m_v2_edits_extrap.nc

# projection of the source datasets, according to the dictionary keys
# create_scrip_file_from_planar_rectangular_grid from MPAS_Tools
src_proj = ais-bedmap2

# number of processors to use for ESMF_RegridWeightGen
nProcs = 128

mesh_gen

landice/crane/default creates a variable resolution mesh. The default is 500m-1km resolution with mesh density determined by observed ice speed and distance to grounding line. 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.