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Interpolation algorithm for ERA5 data to ICON grid changed to bilinear #440

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Interpolation algorithm for ERA5 data to ICON grid changed to bilinear #440

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83d6d76
Interpolation algorithm for ERA5 data to ICON grid changed to bilinear
Jan 27, 2026
3b2cad3
Merge branch 'master' into era_interpolation
ChristianSteger Mar 31, 2026
916bc3e
Interpolation of ERA5 data to ICON/COSMO grid made resolution-depende…
Apr 1, 2026
766928f
GitHub Action: Apply Pep8-formatting
invalid-email-address Apr 1, 2026
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9 changes: 7 additions & 2 deletions python/extpar_era_to_buffer.py
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Original file line number Diff line number Diff line change
Expand Up @@ -144,8 +144,13 @@
logging.info('')

# calculate weights
utils.launch_shell('cdo', '-f', 'nc4', lock, '-P', omp, f'genycon,{grid}',
tg.cdo_sellonlat(), raw_data_sst, weights)
era_5_resolution = 31.0 # approximate ERA5 resolution [km]
if (tg.resolution < era_5_resolution):
utils.launch_shell('cdo', '-f', 'nc4', lock, '-P', omp, f'genbil,{grid}',
tg.cdo_sellonlat(), raw_data_sst, weights)
else:
utils.launch_shell('cdo', '-f', 'nc4', lock, '-P', omp, f'genycon,{grid}',
tg.cdo_sellonlat(), raw_data_sst, weights)

# regrid SST
utils.launch_shell('cdo', '-f', 'nc4', lock, '-P', omp,
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6 changes: 6 additions & 0 deletions python/lib/grid_def.py
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Original file line number Diff line number Diff line change
Expand Up @@ -72,6 +72,9 @@ def __init__(self, namelist):

self.lats, self.lons = self.latlon_cosmo_to_latlon_regular()

self.resolution = (
(2.0 * np.pi * 6.371229 * 10**3) / 360.0 * self.dlon) # [km]

def create_grid_description(self, name):
'''
write grid description required for cdo
Expand Down Expand Up @@ -263,6 +266,9 @@ def __init__(self, gridfile):
self.vlons = np.rad2deg(self.grid.variables["vlon"][:])
self.vlats = np.rad2deg(self.grid.variables["vlat"][:])

self.resolution = (
5050.0 / (self.grid.grid_root * 2**self.grid.grid_level)) # [km]

def cdo_sellonlat(self, dlon=1.0, dlat=1.0):
'''
create the string for the cdo option "-sellonlatbox"
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