The planar_convergence test group (compass.ocean.tests.planar_convergence.PlanarConvergence) implements convergence studies on the full globe. Currently, the only test case is the advection of a cosine bell.


The compass.ocean.tests.planar_convergence.horizontal_advection.HorizontalAdvection test performs a series of 24-day runs that advect a Gaussian-shaped tracer blob across the periodic boundaries and back to its original location. The resolution of the sphere varies (by default, between 2 and 32 km). Advected results are compared with a known exact solution to determine the rate of convergence. See horizontal_advection. for config options and more details on the test case.


The class compass.ocean.tests.planar_convergence.horizontal_advection.init.Init defines a step for setting up the mesh and initial state for each test case with a tracer distributed in a Gaussian shape.


The class compass.ocean.tests.planar_convergence.forward.Forward defines a step for running MPAS-Ocean from the initial condition produced in the initial_state step. The time step is determined from the resolution based on the dt_1km config option. Other namelist options are taken from the test case’s namelist.forward.


The class compass.ocean.tests.planar_convergence.horizontal_advection.analysis.Analysis defines a step for computing the RMSE (root-mean-squared error) for the results at each resolution and plotting them in convergence.png.