from __future__ import print_function
from netCDF4 import Dataset
import numpy as np
[docs]def make_regions_file(filenameIcePresent, filenameMesh,
regionType, varname, limit, filenameOut):
""""
Parameters
----------
filenameIcePresent : str
A filename for a file containing the field specified in ``varname``
that determines where ice may be present
filenameMesh : str
The name of a file containing the MPAS-Seaice mesh
regionType : {"three_region", "two_region_eq", "three_region_eq", "five_region_eq"}
The type of regions to write
varname : str
The name of the variable that determines where ice might be present
limit : float
For ``regionType`` either ``three_region`` or ``five_region_eq``,
the value of the ``varname`` field above which ice is considered to
be present. For other ``regionType`` values, the limit is always 0.5
and this parameter is ignored.
filenameOut : str
The NetCDF filename to write the resulting ``region`` field to
"""
# load ice presence
print(filenameIcePresent)
fileIcePresent = Dataset(filenameIcePresent, "r")
icePresence = fileIcePresent.variables[varname][:]
fileIcePresent.close()
# load mesh data
fileMesh = Dataset(filenameMesh, "r")
nCells = len(fileMesh.dimensions["nCells"])
latCell = fileMesh.variables["latCell"][:]
fileMesh.close()
# output region mask
region = np.zeros(nCells, dtype="i")
# no equatorial removal
if regionType == "three_region":
nRegions = 3
for iCell in range(0, nCells):
if icePresence[iCell] > limit and latCell[iCell] < 0.0:
region[iCell] = 0
elif icePresence[iCell] > limit and latCell[iCell] >= 0.0:
region[iCell] = 2
else:
region[iCell] = 1
elif regionType == "two_region_eq":
nRegions = 2
for iCell in range(0, nCells):
if icePresence[iCell] > 0.5 and latCell[iCell] < 0.0:
region[iCell] = 0
elif icePresence[iCell] > 0.5 and latCell[iCell] >= 0.0:
region[iCell] = 0
else:
region[iCell] = 1
elif regionType == "three_region_eq":
nRegions = 3
for iCell in range(0, nCells):
if icePresence[iCell] > 0.5 and latCell[iCell] < 0.0:
region[iCell] = 0
elif icePresence[iCell] > 0.5 and latCell[iCell] >= 0.0:
region[iCell] = 2
else:
region[iCell] = 1
elif regionType == "five_region_eq":
nRegions = 5
for iCell in range(0, nCells):
if icePresence[iCell] > limit and latCell[iCell] >= 0.0:
region[iCell] = 4
elif limit > icePresence[iCell] > 0.5 and latCell[iCell] >= 0.0:
region[iCell] = 3
elif icePresence[iCell] > limit and latCell[iCell] < 0.0:
region[iCell] = 0
elif limit > icePresence[iCell] > 0.5 and latCell[iCell] < 0.0:
region[iCell] = 1
else:
region[iCell] = 2
else:
raise ValueError(f'Unexpected regionType {regionType}')
# output
fileOut = Dataset(filenameOut, "w", format="NETCDF3_CLASSIC")
fileOut.nRegions = nRegions
fileOut.createDimension("nCells", nCells)
regionVar = fileOut.createVariable("region", "i", dimensions=["nCells"])
regionVar[:] = region[:]
fileOut.close()