def get_stereographic_array_descriptor(self):
# projection for BEDMAP2 and other common Antarctic data sets
projection = pyproj.Proj('+proj=stere +lat_ts=-71.0 +lat_0=-90 '
'+lon_0=0.0 +k_0=1.0 +x_0=0.0 +y_0=0.0 '
'+ellps=WGS84')
# a square 61x61 cell map with 100 km resolution and
xMax = 3000e3
res = 100e3
nx = 2*int(xMax/res)+1
x = numpy.linspace(-xMax, xMax, nx)
descriptor = ProjectionGridDescriptor(projection)
meshName = '{}km_Antarctic_stereo'.format(int(res*1e-3))
descriptor.create(x, x, meshName)
return descriptor
def get_observation_descriptor(self, fileName): # {{{
'''
get a MeshDescriptor for the observation grid
Parameters
----------
fileName : str
observation file name describing the source grid
Returns
-------
obsDescriptor : ``MeshDescriptor``
The descriptor for the observation grid
'''
# Authors
# -------
# Xylar Asay-Davis
# create a descriptor of the observation grid using the x/y polar
# stereographic coordinates
projection = get_antarctic_stereographic_projection()
obsDescriptor = ProjectionGridDescriptor.read(projection,
fileName=fileName,
xVarName='x',
yVarName='y')
return obsDescriptor # }}}
def _get_antarctic_stereographic_comparison_descriptor(config): # {{{
"""
Get a descriptor of an Antarctic steregraphic comparison grid, used for
remapping and determining the grid name
Parameters
----------
config : instance of ``MpasAnalysisConfigParser``
Contains configuration options
Returns
-------
descriptor : ``ProjectionGridDescriptor`` object
A descriptor of the Antarctic comparison grid
"""
# Authors
# -------
# Xylar Asay-Davis
climSection = 'climatology'
comparisonStereoWidth = config.getfloat(climSection,
'comparisonAntarcticStereoWidth')
comparisonStereoResolution = config.getfloat(
climSection, 'comparisonAntarcticStereoResolution')
projection = get_antarctic_stereographic_projection()
xMax = 0.5 * comparisonStereoWidth * 1e3
nx = int(comparisonStereoWidth / comparisonStereoResolution) + 1
x = numpy.linspace(-xMax, xMax, nx)
meshName = '{}x{}km_{}km_Antarctic_stereo'.format(
comparisonStereoWidth, comparisonStereoWidth,
comparisonStereoResolution)
descriptor = ProjectionGridDescriptor.create(projection, x, x, meshName)
return descriptor # }}}
maskedMeltRate = numpy.ma.masked_array(ds.melt_actual,
mask=(ds.melt_actual.values == 0.))
ds['meltRate'] = xarray.DataArray(maskedMeltRate,
dims=ds.melt_actual.dims,
coords=ds.melt_actual.coords,
attrs=ds.melt_actual.attrs)
ds = ds.drop('melt_actual')
inGridName = '{}x{}km_1.0km_Antarctic_stereo'.format(lx, ly)
projection = pyproj.Proj('+proj=stere +lat_ts=-71.0 +lat_0=-90 +lon_0=0.0 '
'+k_0=1.0 +x_0=0.0 +y_0=0.0 +ellps=WGS84')
inDescriptor = ProjectionGridDescriptor(projection)
inDescriptor.read(inFileName,
xVarName='xaxis',
yVarName='yaxis',
meshName=inGridName)
outDescriptor = get_Antarctic_stereographic_comparison_descriptor(config)
outGridName = outDescriptor.meshName
outFileName = 'Rignot_2013_melt_rates_{}.nc'.format(outGridName)
mappingFileName = 'map_{}_to_{}.nc'.format(inGridName, outGridName)
remapper = Remapper(inDescriptor, outDescriptor, mappingFileName)
