Spherical grid with an idealized bathymetry

1. Import Modules

[1]:

%%capture

from mom6_forge.grid import Grid
from mom6_forge.topo import Topo

2. Create a horizontal MOM6 grid

Spherical grid (360 x 160 deg). Grid spacing (dx, dy) = 2 deg

[2]:

# Instantiate a MOM6 grid instance
grid = Grid(
    nx         = 180,     # Number of grid points in x direction
    ny         = 80,      # Number of grid points in y direction
    lenx       = 360.0,   # grid length in x direction (degrees)
    leny       = 160.0,   # grid length in y direction (degrees)
    cyclic_x   = True,    # non-reentrant, rectangular domain
)

Plot grid properties:

[3]:

grid.tlat.plot();

../_images/notebooks_1_spherical_grid_6_0.png

[4]:

grid.tlon.plot();

../_images/notebooks_1_spherical_grid_7_0.png

3. Configure the bathymetry

[5]:

# Instantiate a Topo object associated with the horizontal grid object (grid).
topo = Topo(grid, min_depth=10.0)

Predefined idealized bathymetries:

Topo class provides three idealized bathymetry options, which are also provided by MOM6 as out-of-the-box idealized bathymetry options:

flat bottom: flat bottom set to MAXIMUM_DEPTH.
bowl: an analytically specified bowl-shaped basin ranging between MAXIMUM_DEPTH and MINIMUM_DEPTH.
spoon: a similar shape to ‘bowl’, but with an vertical wall at the southern face.

flat bottom bathymetry

[6]:

# Set the bathymetry to be a flat bottom with a depth of 2000m
topo.set_flat(D=2000.0)

[7]:

topo.depth.plot()

[7]:

<matplotlib.collections.QuadMesh at 0x1517d1159910>

../_images/notebooks_1_spherical_grid_13_1.png

spoon bathymetry

[8]:

topo.set_spoon(500.0, 50.0, expdecay=1e8)

[9]:

topo.depth.plot()

[9]:

<matplotlib.collections.QuadMesh at 0x1517d11a5410>

../_images/notebooks_1_spherical_grid_16_1.png

bowl bathymetry

[10]:

topo.set_bowl(100.0, 0.0, expdecay=1e8)

[11]:

topo.depth.plot()

[11]:

<matplotlib.collections.QuadMesh at 0x1517d461cb50>

../_images/notebooks_1_spherical_grid_19_1.png

[12]:

topo.tmask.plot()

[12]:

<matplotlib.collections.QuadMesh at 0x1517d4762fd0>

../_images/notebooks_1_spherical_grid_20_1.png

[13]:

topo._grid.tarea.plot()

[13]:

<matplotlib.collections.QuadMesh at 0x1517d126da50>

../_images/notebooks_1_spherical_grid_21_1.png

4. Save the grid and bathymetry files

[14]:

# MOM6 supergrid file:
grid.write_supergrid("./ocean_hgrid_1.nc")

# MOM6 topography file:
topo.write_topo("./ocean_topog_1.nc")

# CICE grid file:
topo.write_cice_grid("./cice_grid_1.nc")

# SCRIP grid file (for runoff remapping, if needed):
topo.write_scrip_grid("./scrip_grid_1.nc")

# ESMF mesh file:
topo.write_esmf_mesh("./ESMF_mesh_1.nc")

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