The landice/hydro_radial test group implements variants of the radially symmetric hydrological test case from Bueler and van Pelt (2015). The test case uses semi-analytic solutions for water depth and water pressure for an ice sheet with prescribed ice thickness and sliding speed.


Profiles of modeled water depth (W) and water pressure (P_w) compared to the semi-exact solution of Bueler and van Pelt (2015)

The domain is approximately rectangular with a radially symmetric ice sheet at its center. The mesh has 1-km horizontal resolution.

The test group includes 4 test cases. All test cases are made up of 3 types of steps, setup_mesh, which defines the mesh and initial conditions for the model; run_model (given another name in many test cases to distinguish multiple forward runs), which performs time integration of the model; and visualize, which optionally plots the results of the test case (PNG files, plot windows, or both).

config options

All 4 test cases share the same set of default config options:

# config options for hydro_radial test cases

# sizes (in cells) for the 1000m uniform mesh
nx = 50
ny = 58

# resolution (in m) for the 1000m uniform mesh
dc = 1000.0

# number of levels in the mesh
levels = 3

# config options related to visualization for hydro_radial test cases

# which time index to visualize
time_slice = -1

# whether to save image files
save_images = True

# whether to hide figures (typically when save_images = True)
hide_figs = True


landice/hydro_radial/spinup_test performs a 10,000-year spin-up run from “zero” (a very thin ice initial water layer) to quasi-steady state. This takes about 10 minutes on 128 processors (1 cpu node) on Perlmutter.


landice/hydro_radial/steady_state_drift_test performs a 1-month run, starting from the “exact” (that is, a nearly exact steady-state solution) as the initial condition. The model drift away from the initialized exact solution can be used as a metric of model error. See figure 3 in Hoffman, Matthew J., et al. 2018. “MPAS-Albany Land Ice (MALI): A Variable-Resolution Ice Sheet Model for Earth System Modeling Using Voronoi Grids.” Geoscientific Model Development 11 (9): 3747–80. https://doi.org/10.5194/gmd-11-3747-2018.


landice/hydro_radial/decomposition_test runs the steady state drift test on 1 (1proc_run step) and then on 3 cores (3proc_run step) to make sure the resulting prognostic variables are bit-for-bit identical between the two runs.


landice/hydro_radial/restart_test first run a 2-month integration of the model forward in time (full_run step). Then, a second step (restart_run) performs 2 1-month runs, where the second begins from a restart file saved by the first. Prognostic variables are compared between the “full” and “restart” runs at the end of 2 months to make sure they are bit-for-bit identical. This test is set up as in the steady_state_drift_test and decomposition_test but runs for a total of two months instead of one.