# Read zonal and meridional wind components from file using the iris module.
# The components are in separate files. We catch warnings here because the
# files are not completely CF compliant.
with warnings.catch_warnings():
warnings.simplefilter('ignore', UserWarning)
uwnd = iris.load_cube(example_data_path('uwnd_mean.nc'))
vwnd = iris.load_cube(example_data_path('vwnd_mean.nc'))
uwnd.coord('longitude').circular = True
vwnd.coord('longitude').circular = True
# Create a VectorWind instance to handle the computation of streamfunction and
# velocity potential.
w = VectorWind(uwnd, vwnd)
# Compute the streamfunction and velocity potential.
sf, vp = w.sfvp()
# Pick out the field for December.
time_constraint = iris.Constraint(month='Dec')
add_month(sf, 'time', name='month')
add_month(vp, 'time', name='month')
sf_dec = sf.extract(time_constraint)
vp_dec = vp.extract(time_constraint)
# Plot streamfunction.
clevs = [-120, -100, -80, -60, -40, -20, 0, 20, 40, 60, 80, 100, 120]
ax = plt.subplot(111, projection=ccrs.PlateCarree(central_longitude=180))
fill_sf = iplt.contourf(sf_dec * 1e-06, clevs, cmap=plt.cm.RdBu_r,
extend='both')
ax.coastlines()
ax.gridlines()
# Read zonal and meridional wind components from file using the iris module.
# The components are in separate files. We catch warnings here because the
# files are not completely CF compliant.
with warnings.catch_warnings():
warnings.simplefilter('ignore', UserWarning)
uwnd = iris.load_cube(example_data_path('uwnd_mean.nc'))
vwnd = iris.load_cube(example_data_path('vwnd_mean.nc'))
uwnd.coord('longitude').circular = True
vwnd.coord('longitude').circular = True
# Create a VectorWind instance to handle the computation of streamfunction and
# velocity potential.
w = VectorWind(uwnd, vwnd)
# Compute the streamfunction and velocity potential.
sf, vp = w.sfvp()
# Pick out the field for December.
time_constraint = iris.Constraint(month='Dec')
add_month(sf, 'time', name='month')
add_month(vp, 'time', name='month')
sf_dec = sf.extract(time_constraint)
vp_dec = vp.extract(time_constraint)
# Plot streamfunction.
clevs = [-120, -100, -80, -60, -40, -20, 0, 20, 40, 60, 80, 100, 120]
ax = plt.subplot(111, projection=ccrs.PlateCarree(central_longitude=180))
fill_sf = iplt.contourf(sf_dec * 1e-06,
clevs,
cmap=plt.cm.RdBu_r,
extend='both')
