hurricane

The hurricane test group implements regionally refined, single layer barotropic, tropical cyclone cases as described in hurricane in the User’s Guide.

The hurricane test group uses the MPAS-Ocean wetting and drying scheme to simulate coastal flooding due to storm surge. Three wetting and drying options are accepted as a wetdry argument into the Init and Forward cases (off, standard, subgrid). If subgrid is used, the test group will build look-up tables from a high-resolution DEM in order to apply the Shallow Water Subgrid scheme corrections to the barotropic momentum equations.

The hurricane test group also supports two local time-stepping schemes (LTS, FB-LTS), passed as the use_lts argument in the Mesh, Init and Forward cases.

Meshes

The hurricane test group supports 3 meshes (DEQU120at30cr10rr2, DEVR45to5rr1, RRS6to18). Each mesh inherits from the compass.ocean.mesh.floodplain.FloodplainMeshStep class, and provides a build_cell_width_lat_lon() method to specify the mesh resolution array using the mpas_tools.ocean.coastal_tools.coastal_refined_mesh() function. Each mesh also uses config options to determine how the floodplain is defined.

DEQU120at30cr10rr2

The DEQU120at30cr10rr2 mesh is a quasi-uniform, 120 km horizontal resoution global mesh with regional refinement along the Mid-Atlantic Bight down to 2 km. The mesh is defined by compass.ocean.tests.hurricane.mesh.dequ120at30cr10rr2.DEQU120at30cr10rr2BaseMesh.

The default config options for this mesh are:

# options for spherical meshes
[spherical_mesh]

## config options related to the step for culling land from the mesh
# number of cores to use
cull_mesh_cpus_per_task = 18
# minimum of cores, below which the step fails
cull_mesh_min_cpus_per_task = 1
# maximum memory usage allowed (in MB)
cull_mesh_max_memory = 1000

# Elevation threshold to use for including land cells
floodplain_elevation = 10.0


# options for hurricane testcases
[hurricane]

## config options related to the initial_state step
# number of MPI tasks to use
init_ntasks = 36
# minimum of MPI tasks, below which the step fails
init_min_tasks = 8
# maximum memory usage allowed (in MB)
init_max_memory = 1000
# number of threads
init_threads = 1

## config options related to the forward steps
# number of MPI tasks to use
forward_ntasks = 180
# minimum of MPI tasks, below which the step fails
forward_min_tasks = 18
# maximum memory usage allowed (in MB)
forward_max_memory = 1000
# number of threads
forward_threads = 1

DEVR45to5rr1

The DEVR45to5rr1 mesh is a variable-resolution 45 km to 5 km global mesh with regional refinement along the Mid-Atlantic Bight down to 1 km. The mesh is defined by compass.ocean.tests.hurricane.mesh.devr45to5rr1.DEVR45to5rr1BaseMesh.

The default config options for this mesh are:

# options for spherical meshes
[spherical_mesh]

## config options related to the step for culling land from the mesh
# number of cores to use
cull_mesh_cpus_per_task = 18
# minimum of cores, below which the step fails
cull_mesh_min_cpus_per_task = 1
# maximum memory usage allowed (in MB)
cull_mesh_max_memory = 1000

# Elevation threshold to use for including land cells
floodplain_elevation = 40.0
# Resolution threshold to use for including land cells
floodplain_resolution = 4.0
# Minimum depth to enforce outside floodplain region
min_depth_outside_floodplain = 1.0


# options for hurricane testcases
[hurricane]

## config options related to the initial_state step
# number of MPI tasks to use
init_ntasks = 512
# minimum of MPI tasks, below which the step fails
init_min_tasks = 512
# maximum memory usage allowed (in MB)
init_max_memory = 1000
# number of threads
init_threads = 1

## config options related to the forward steps
# number of MPI tasks to use
forward_ntasks = 1024
# minimum of MPI tasks, below which the step fails
forward_min_tasks = 1024
# maximum memory usage allowed (in MB)
forward_max_memory = 1000
# number of threads
forward_threads = 1

RRS6to18

The RRS6to18 mesh is a high-resolution global mesh with Rossby-radius-scaling of horizontal resolution from 18 km down to 6 km. The mesh is defined by compass.ocean.tests.hurricane.mesh.rrs6to18.RRS6to18BaseMesh.

The default config options for this mesh are:

# options for spherical meshes
[spherical_mesh]

## config options related to the step for culling land from the mesh
convert_culled_mesh_to_cdf5 = True
# number of cores to use
cull_mesh_cpus_per_task = 18
# minimum of cores, below which the step fails
cull_mesh_min_cpus_per_task = 1
# maximum memory usage allowed (in MB)
cull_mesh_max_memory = 1000

# Elevation threshold to use for including land cells
floodplain_elevation = 20.0
# Resolution threshold to use for including land cells
floodplain_resolution = 16.0
floodplain_geojson = mab_floodplain.geojson
# Minimum depth to enforce outside floodplain region
min_depth_outside_floodplain = 1.0


# options for hurricane testcases
[hurricane]

## config options related to the initial_state step
# number of MPI tasks to use
init_ntasks = 512
# minimum of MPI tasks, below which the step fails
init_min_tasks = 1
# maximum memory usage allowed (in MB)
init_max_memory = 1000
# number of threads
init_threads = 1

## config options related to the forward steps
# number of MPI tasks to use
forward_ntasks = 1024
# minimum of MPI tasks, below which the step fails
forward_min_tasks = 1024
# maximum memory usage allowed (in MB)
forward_max_memory = 1000
# number of threads
forward_threads = 1

Test cases

mesh test case

The mesh test case generates an MPAS horizontal mesh, then culls out the land cells to improve model efficiency. For hurricane meshes, the culling step preserves a coastal floodplain according to config options. The compass.ocean.tests.hurricane.mesh.Mesh class is instantiated with the desired mesh name in order to build the mesh.

If either of the local time-stepping schemes (LTS, FB-LTS) are enabled, the compass.ocean.tests.hurricane.lts.mesh.lts_regions.LTSRegionsStep class creates a copy of the culled mesh file that additionally includes an array called LTSRegion. This array has appropriate flags that determine what time-step should be used on a certain cell of the mesh, according to the local-time stepping scheme. The graph.info file is also copied and modified to address proper load balancing. The aforementioned class receives the compass.ocean.mesh.cull.CullMeshStep as input.

init test case

The init test performs steps to set up the vertical mesh, initial conditions, atmospheric forcing, and parameterized wave and bottom drag, and prepares the station locations for timeseries output.

initial_state

The class compass.ocean.tests.hurricane.init.initial_state.InitialState defines a step for running MPAS-Ocean in init mode. The vertical mesh is set up with a single layer. For the subgrid scheme, the initial_state step is where the wetdry parameter determines whether to build the subgrid look-up tables and construct the floodplain topography averaged from the high-resolution DEM.

interpolate_atm_forcing

The class compass.ocean.tests.hurricane.init.interpolate_atm_forcing.InterpolateAtmForcing defines a step for interpolating CFSv2 reanalysis data for atmospheric winds and pressure onto the MPAS-Ocean mesh at hourly time intervals. The forward run uses this as input to update the time varying atmospheric forcing.

create_pointstats_file

The class compass.ocean.tests.hurricane.init.create_pointstats_file.CreatePointstatsFile defines a step to create the input file for the MPAS-Ocean pointWiseStats analysis member based on station locations which have observed data.

topographic_wave_drag

The class compass.ocean.tests.hurricane.lts.init.topographic_wave_drag.ComputeTopographicWaveDrag defines a step for interpolating the reciprocal of the r_inv to the mesh edges. This step is needed to include the contribution of the topographic wave drag in the model momentum tendency.

sandy test case

The sandy test case is responsible for the forward model simulation and analysis.

forward

The class compass.ocean.tests.hurricane.forward.forward.ForwardStep defines a step to run MPAS-Ocean in forward mode. For the subgrid scheme, the forward step is where the wetdry parameter determines whether to apply the subgrid corrections via the look-up tables built in the initial_state step.

analysis

The class compass.ocean.tests.hurricane.analysis.Analysis defines a step to generate validation plots comparing sea surface height timeseries between modeled and observed data at several different stations. Both NOAA and USGS observations are plotted.