rotation_2d

The polaris.ocean.tasks.sphere_transport.SphereTransport rotation_2d test performs a 12-day run on the sphere that has a flow with a constant rotation rate which affects tracer distributions. The resolution of the sphere varies (by default, between 60 and 240 km). After one period, the tracer distributions are compared the initial condition to evaluate numerical errors associated with the horizontal advection scheme and determine the rate of convergence.

framework

The config options for the rotation_2d test is described in rotation 2-d in the User’s Guide.

Additionally, the test uses a forward.yaml file with a few common model config options related to drag and default horizontal and vertical momentum and tracer diffusion, as well as defining mesh, input, restart, and output streams. This file has Jinja templating that is used to update model config options based on Polaris config options, see Convergence Tests.

base_mesh

Sphere transport tasks use shared base_mesh steps for creating Quasi-uniform and Icosahedral Spherical Meshes at a sequence of resolutions.

init

The class polaris.ocean.tasks.sphere_transport.init.Init defines a step for setting up the initial state at each resolution. The initial state is differentiated between rotation_2d and the other tests set up by the class.

forward

The class polaris.ocean.tasks.sphere_transport.forward.Forward descends from polaris.ocean.convergence.spherical.SphericalConvergenceForward, and defines a step for running MPAS-Ocean from an initial condition produced in an init step. See Convergence Tests for some relevant discussion of the parent class. The time step is determined from the resolution based on the dt_per_km config option in the [convergence_forward] section. Other model config options are taken from forward.yaml.

analysis

The class polaris.ocean.tasks.sphere_transport.analysis.Analysis descends from polaris.ocean.convergence.ConvergenceAnalysis, and defines a step for computing the error norm (L2) for the results at each resolution for tracers and layer thickness, saving them in convergence_*.csv and plotting them in convergence_*.png.

viz

Visualization step is available only in the rotation_2d/with_viz tasks. It is not included in the rotation_2d in order to keep regression as fast as possible when visualization isn’t needed.

The class polaris.ocean.tasks.sphere_transport.viz.Viz is a step for plotting the initial and final states of the advection test for each resolution. The colormap is controlled by these options:

# options for visualization for the sphere transport test case
[sphere_transport_viz_*]

# colormap options
# colormap
colormap_name = viridis

# [optional] colormap set_under and set_over options
under_color = k
over_color = orange

# the type of norm used in the colormap
norm_type = linear

# colorbar limits
colorbar_limits = 0., 1.

See global lat/lon plots for more details.