Regrid xarray Dataset with multiple variables

[1]:

%matplotlib inline
import matplotlib.pyplot as plt
import numpy as np
import xarray as xr
import xesmf as xe

Starting v0.2.0, xESMF is able to take xarray.Dataset as input data, and automatically loop over all variables.

A simple example

Prepare input data

[2]:

ds = xr.tutorial.open_dataset("air_temperature")
ds  # air temperature in Kelvin

[2]:
Show/Hide data repr Show/Hide attributes
xarray.Dataset
    • lat: 25
    • lon: 53
    • time: 2920
    • lat
      (lat)
      float32
      75.0 72.5 70.0 ... 20.0 17.5 15.0
      standard_name :
      latitude
      long_name :
      Latitude
      units :
      degrees_north
      axis :
      Y
      array([75. , 72.5, 70. , 67.5, 65. , 62.5, 60. , 57.5, 55. , 52.5, 50. , 47.5,
       45. , 42.5, 40. , 37.5, 35. , 32.5, 30. , 27.5, 25. , 22.5, 20. , 17.5,
       15. ], dtype=float32)
    • lon
      (lon)
      float32
      200.0 202.5 205.0 ... 327.5 330.0
      standard_name :
      longitude
      long_name :
      Longitude
      units :
      degrees_east
      axis :
      X
      array([200. , 202.5, 205. , 207.5, 210. , 212.5, 215. , 217.5, 220. , 222.5,
       225. , 227.5, 230. , 232.5, 235. , 237.5, 240. , 242.5, 245. , 247.5,
       250. , 252.5, 255. , 257.5, 260. , 262.5, 265. , 267.5, 270. , 272.5,
       275. , 277.5, 280. , 282.5, 285. , 287.5, 290. , 292.5, 295. , 297.5,
       300. , 302.5, 305. , 307.5, 310. , 312.5, 315. , 317.5, 320. , 322.5,
       325. , 327.5, 330. ], dtype=float32)
    • time
      (time)
      datetime64[ns]
      2013-01-01 ... 2014-12-31T18:00:00
      standard_name :
      time
      long_name :
      Time
      array(['2013-01-01T00:00:00.000000000', '2013-01-01T06:00:00.000000000',
       '2013-01-01T12:00:00.000000000', ..., '2014-12-31T06:00:00.000000000',
       '2014-12-31T12:00:00.000000000', '2014-12-31T18:00:00.000000000'],
      dtype='datetime64[ns]')
    • air
      (time, lat, lon)
      float32
      ...
      long_name :
      4xDaily Air temperature at sigma level 995
      units :
      degK
      precision :
      2
      GRIB_id :
      11
      GRIB_name :
      TMP
      var_desc :
      Air temperature
      dataset :
      NMC Reanalysis
      level_desc :
      Surface
      statistic :
      Individual Obs
      parent_stat :
      Other
      actual_range :
      [185.16 322.1 ]
      [3869000 values with dtype=float32]
  • Conventions :
    COARDS
    title :
    4x daily NMC reanalysis (1948)
    description :
    Data is from NMC initialized reanalysis (4x/day). These are the 0.9950 sigma level values.
    platform :
    Model
    references :
    http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html
[3]:

# input dataset can contain variables of different shapes (e.g. 2D, 3D, 4D), as long as horizontal shapes are the same.
ds["celsius"] = ds["air"] - 273.15  # Kelvin -> celsius
ds["slice"] = ds["air"].isel(time=0)
ds

[3]:
Show/Hide data repr Show/Hide attributes
xarray.Dataset
    • lat: 25
    • lon: 53
    • time: 2920
    • lat
      (lat)
      float32
      75.0 72.5 70.0 ... 20.0 17.5 15.0
      standard_name :
      latitude
      long_name :
      Latitude
      units :
      degrees_north
      axis :
      Y
      array([75. , 72.5, 70. , 67.5, 65. , 62.5, 60. , 57.5, 55. , 52.5, 50. , 47.5,
       45. , 42.5, 40. , 37.5, 35. , 32.5, 30. , 27.5, 25. , 22.5, 20. , 17.5,
       15. ], dtype=float32)
    • lon
      (lon)
      float32
      200.0 202.5 205.0 ... 327.5 330.0
      standard_name :
      longitude
      long_name :
      Longitude
      units :
      degrees_east
      axis :
      X
      array([200. , 202.5, 205. , 207.5, 210. , 212.5, 215. , 217.5, 220. , 222.5,
       225. , 227.5, 230. , 232.5, 235. , 237.5, 240. , 242.5, 245. , 247.5,
       250. , 252.5, 255. , 257.5, 260. , 262.5, 265. , 267.5, 270. , 272.5,
       275. , 277.5, 280. , 282.5, 285. , 287.5, 290. , 292.5, 295. , 297.5,
       300. , 302.5, 305. , 307.5, 310. , 312.5, 315. , 317.5, 320. , 322.5,
       325. , 327.5, 330. ], dtype=float32)
    • time
      (time)
      datetime64[ns]
      2013-01-01 ... 2014-12-31T18:00:00
      standard_name :
      time
      long_name :
      Time
      array(['2013-01-01T00:00:00.000000000', '2013-01-01T06:00:00.000000000',
       '2013-01-01T12:00:00.000000000', ..., '2014-12-31T06:00:00.000000000',
       '2014-12-31T12:00:00.000000000', '2014-12-31T18:00:00.000000000'],
      dtype='datetime64[ns]')
    • air
      (time, lat, lon)
      float32
      241.2 242.5 243.5 ... 296.19 295.69
      long_name :
      4xDaily Air temperature at sigma level 995
      units :
      degK
      precision :
      2
      GRIB_id :
      11
      GRIB_name :
      TMP
      var_desc :
      Air temperature
      dataset :
      NMC Reanalysis
      level_desc :
      Surface
      statistic :
      Individual Obs
      parent_stat :
      Other
      actual_range :
      [185.16 322.1 ]
      array([[[241.2    , 242.5    , ..., 235.5    , 238.59999],
        [243.79999, 244.5    , ..., 235.29999, 239.29999],
        ...,
        [295.9    , 296.19998, ..., 295.9    , 295.19998],
        [296.29   , 296.79   , ..., 296.79   , 296.6    ]],

       [[242.09999, 242.7    , ..., 233.59999, 235.79999],
        [243.59999, 244.09999, ..., 232.5    , 235.7    ],
        ...,
        [296.19998, 296.69998, ..., 295.5    , 295.1    ],
        [296.29   , 297.19998, ..., 296.4    , 296.6    ]],

       ...,

       [[245.79   , 244.79   , ..., 243.98999, 244.79   ],
        [249.89   , 249.29   , ..., 242.48999, 244.29   ],
        ...,
        [296.29   , 297.19   , ..., 295.09   , 294.38998],
        [297.79   , 298.38998, ..., 295.49   , 295.19   ]],

       [[245.09   , 244.29   , ..., 241.48999, 241.79   ],
        [249.89   , 249.29   , ..., 240.29   , 241.68999],
        ...,
        [296.09   , 296.88998, ..., 295.69   , 295.19   ],
        [297.69   , 298.09   , ..., 296.19   , 295.69   ]]], dtype=float32)
    • celsius
      (time, lat, lon)
      float32
      -31.949997 -30.649994 ... 22.540009
      array([[[-31.949997, -30.649994, -29.649994, ..., -40.350006,
         -37.649994, -34.550003],
        [-29.350006, -28.649994, -28.449997, ..., -40.350006,
         -37.850006, -33.850006],
        [-23.149994, -23.350006, -24.259995, ..., -39.949997,
         -36.759995, -31.449997],
        ...,
        [ 23.450012,  23.049988,  23.25    , ...,  22.25    ,
          21.950012,  21.549988],
        [ 22.75    ,  23.049988,  23.640015, ...,  22.75    ,
          22.75    ,  22.049988],
        [ 23.140015,  23.640015,  23.950012, ...,  23.75    ,
          23.640015,  23.450012]],

       [[-31.050003, -30.449997, -30.050003, ..., -41.149994,
         -39.550003, -37.350006],
        [-29.550003, -29.050003, -28.949997, ..., -42.149994,
         -40.649994, -37.449997],
        [-19.949997, -20.259995, -21.050003, ..., -42.350006,
         -39.759995, -34.649994],
        ...,
        [ 23.25    ,  22.75    ,  23.049988, ...,  22.25    ,
          21.950012,  21.640015],
        [ 23.049988,  23.549988,  23.640015, ...,  22.450012,
          22.350006,  21.950012],
        [ 23.140015,  24.049988,  24.25    , ...,  23.25    ,
          23.25    ,  23.450012]],

       [[-30.850006, -30.949997, -30.850006, ..., -38.850006,
         -37.050003, -34.449997],
        [-28.550003, -28.759995, -29.149994, ..., -42.850006,
         -41.149994, -37.449997],
        [-16.950012, -17.649994, -18.949997, ..., -41.949997,
         -39.949997, -34.949997],
        ...,
        [ 22.450012,  22.25    ,  22.25    , ...,  23.140015,
          22.140015,  21.850006],
        [ 23.049988,  23.350006,  23.140015, ...,  23.25    ,
          22.850006,  22.450012],
        [ 23.25    ,  23.140015,  23.25    , ...,  23.850006,
          23.850006,  23.640015]],

       ...,

       [[-29.660004, -30.160004, -31.059998, ..., -28.960007,
         -28.660004, -28.259995],
        [-24.059998, -24.160004, -24.559998, ..., -32.559998,
         -31.86    , -30.460007],
        [-10.459991, -10.959991, -11.459991, ..., -33.759995,
         -31.460007, -27.960007],
        ...,
        [ 21.640015,  22.140015,  24.339996, ...,  22.339996,
          22.23999 ,  21.540009],
        [ 23.640015,  24.73999 ,  25.140015, ...,  22.339996,
          22.339996,  21.640015],
        [ 25.040009,  26.040009,  25.640015, ...,  22.940002,
          22.640015,  22.640015]],

       [[-27.36    , -28.36    , -29.660004, ..., -29.86    ,
         -29.160004, -28.36    ],
        [-23.259995, -23.86    , -24.660004, ..., -31.86    ,
         -30.660004, -28.86    ],
        [-10.76001 , -11.359985, -11.859985, ..., -32.660004,
         -30.059998, -26.259995],
        ...,
        [ 20.540009,  20.73999 ,  22.23999 , ...,  21.940002,
          21.540009,  21.140015],
        [ 23.140015,  24.040009,  24.440002, ...,  22.140015,
          21.940002,  21.23999 ],
        [ 24.640015,  25.23999 ,  25.339996, ...,  22.540009,
          22.339996,  22.040009]],

       [[-28.059998, -28.86    , -29.86    , ..., -31.460007,
         -31.660004, -31.36    ],
        [-23.259995, -23.86    , -24.759995, ..., -33.559998,
         -32.86    , -31.460007],
        [-10.160004, -10.959991, -11.76001 , ..., -33.259995,
         -30.559998, -26.86    ],
        ...,
        [ 20.640015,  20.540009,  21.940002, ...,  22.140015,
          21.940002,  21.540009],
        [ 22.940002,  23.73999 ,  24.040009, ...,  22.540009,
          22.540009,  22.040009],
        [ 24.540009,  24.940002,  24.940002, ...,  23.339996,
          23.040009,  22.540009]]], dtype=float32)
    • slice
      (lat, lon)
      float32
      241.2 242.5 243.5 ... 296.79 296.6
      long_name :
      4xDaily Air temperature at sigma level 995
      units :
      degK
      precision :
      2
      GRIB_id :
      11
      GRIB_name :
      TMP
      var_desc :
      Air temperature
      dataset :
      NMC Reanalysis
      level_desc :
      Surface
      statistic :
      Individual Obs
      parent_stat :
      Other
      actual_range :
      [185.16 322.1 ]
      array([[241.2    , 242.5    , 243.5    , ..., 232.79999, 235.5    , 238.59999],
       [243.79999, 244.5    , 244.7    , ..., 232.79999, 235.29999, 239.29999],
       [250.     , 249.79999, 248.89   , ..., 233.2    , 236.39   , 241.7    ],
       ...,
       [296.6    , 296.19998, 296.4    , ..., 295.4    , 295.1    , 294.69998],
       [295.9    , 296.19998, 296.79   , ..., 295.9    , 295.9    , 295.19998],
       [296.29   , 296.79   , 297.1    , ..., 296.9    , 296.79   , 296.6    ]],
      dtype=float32)
  • Conventions :
    COARDS
    title :
    4x daily NMC reanalysis (1948)
    description :
    Data is from NMC initialized reanalysis (4x/day). These are the 0.9950 sigma level values.
    platform :
    Model
    references :
    http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html

Build regridder

[4]:

ds_out = xr.Dataset(
    {
        "lat": (["lat"], np.arange(16, 75, 1.0)),
        "lon": (["lon"], np.arange(200, 330, 1.5)),
    }
)

regridder = xe.Regridder(ds, ds_out, "bilinear")
regridder

[4]:

xESMF Regridder
Regridding algorithm:       bilinear
Input grid shape:           (25, 53)
Output grid shape:          (59, 87)
Output grid dimension name: ('lat', 'lon')
Periodic in longitude?      False

Apply to data

[5]:

# the entire dataset can be processed at once
ds_out = regridder(ds)
ds_out

using dimensions ('lat', 'lon') from data variable air as the horizontal dimensions for this dataset.

[5]:
Show/Hide data repr Show/Hide attributes
xarray.Dataset
    • lat: 59
    • lon: 87
    • time: 2920
    • time
      (time)
      datetime64[ns]
      2013-01-01 ... 2014-12-31T18:00:00
      standard_name :
      time
      long_name :
      Time
      array(['2013-01-01T00:00:00.000000000', '2013-01-01T06:00:00.000000000',
       '2013-01-01T12:00:00.000000000', ..., '2014-12-31T06:00:00.000000000',
       '2014-12-31T12:00:00.000000000', '2014-12-31T18:00:00.000000000'],
      dtype='datetime64[ns]')
    • lon
      (lon)
      float64
      200.0 201.5 203.0 ... 327.5 329.0
      array([200. , 201.5, 203. , 204.5, 206. , 207.5, 209. , 210.5, 212. , 213.5,
       215. , 216.5, 218. , 219.5, 221. , 222.5, 224. , 225.5, 227. , 228.5,
       230. , 231.5, 233. , 234.5, 236. , 237.5, 239. , 240.5, 242. , 243.5,
       245. , 246.5, 248. , 249.5, 251. , 252.5, 254. , 255.5, 257. , 258.5,
       260. , 261.5, 263. , 264.5, 266. , 267.5, 269. , 270.5, 272. , 273.5,
       275. , 276.5, 278. , 279.5, 281. , 282.5, 284. , 285.5, 287. , 288.5,
       290. , 291.5, 293. , 294.5, 296. , 297.5, 299. , 300.5, 302. , 303.5,
       305. , 306.5, 308. , 309.5, 311. , 312.5, 314. , 315.5, 317. , 318.5,
       320. , 321.5, 323. , 324.5, 326. , 327.5, 329. ])
    • lat
      (lat)
      float64
      16.0 17.0 18.0 ... 72.0 73.0 74.0
      array([16., 17., 18., 19., 20., 21., 22., 23., 24., 25., 26., 27., 28., 29.,
       30., 31., 32., 33., 34., 35., 36., 37., 38., 39., 40., 41., 42., 43.,
       44., 45., 46., 47., 48., 49., 50., 51., 52., 53., 54., 55., 56., 57.,
       58., 59., 60., 61., 62., 63., 64., 65., 66., 67., 68., 69., 70., 71.,
       72., 73., 74.])
    • air
      (time, lat, lon)
      float64
      296.1 296.4 296.6 ... 241.0 241.5
      array([[[296.13399675, 296.38669304, 296.63889823, ..., 296.47490793,
         296.43398913, 296.19924566],
        [295.97800871, 296.18274797, 296.42534501, ..., 296.09262341,
         296.07802394, 295.72098714],
        [296.04001766, 296.13556275, 296.30247974, ..., 295.77692914,
         295.73997197, 295.35693248],
        ...,
        [245.04017912, 245.36087049, 245.56096188, ..., 233.93629106,
         235.51802332, 238.0780694 ],
        [243.27991042, 243.77519503, 244.17375053, ..., 233.81591274,
         235.33999633, 237.63241841],
        [242.24003289, 242.87912303, 243.43775032, ..., 233.84791841,
         235.41999207, 237.49641598]],

       [[296.25399643, 296.70203773, 297.03166485, ..., 296.06514956,
         296.03998263, 296.01773136],
        [296.2179898 , 296.56767711, 296.82291528, ..., 295.7292558 ,
         295.6800262 , 295.5138904 ],
        [296.23999022, 296.42058286, 296.56714652, ..., 295.50442291,
         295.41998903, 295.19133215],
        ...,
        [245.52028453, 245.73709231, 245.85148963, ..., 231.64759509,
         232.67802699, 234.83033953],
        [243.29994515, 243.61404829, 243.85326489, ..., 231.80653129,
         232.72003168, 234.51923375],
        [242.70001369, 243.03800427, 243.31726258, ..., 232.22256285,
         233.15997775, 234.71925176]],

       [[296.31998597, 296.35233477, 296.37027072, ..., 296.69703874,
         296.59998477, 296.42993717],
        [296.23999022, 296.37072264, 296.42865111, ..., 296.39312798,
         296.20003046, 295.98447426],
        [296.07996829, 296.20134835, 296.24744824, ..., 296.17051878,
         295.85798008, 295.63218076],
        ...,
        [246.92034241, 246.75294557, 246.50912779, ..., 231.18562131,
         232.24003595, 234.61904532],
        [244.13992017, 244.03040136, 243.89556811, ..., 231.78222568,
         232.82012307, 234.90301222],
        [243.22002405, 243.13672999, 243.05876072, ..., 233.39835074,
         234.45993206, 236.27912467]],

       ...,

       [[297.62998356, 298.25582152, 298.65503226, ..., 295.7786526 ,
         295.66999665, 295.50299763],
        [297.07004997, 297.7199817 , 298.19914665, ..., 295.58670885,
         295.55000304, 295.2150872 ],
        [296.38994762, 296.98154159, 297.52424514, ..., 295.48204978,
         295.46998597, 295.05016151],
        ...,
        [251.81041188, 251.72296686, 251.55990593, ..., 240.75713161,
         241.37000425, 242.46456685],
        [247.96982451, 247.87036819, 247.69574495, ..., 241.55307104,
         241.93009016, 242.64624471],
        [245.73007797, 245.53418764, 245.25570503, ..., 242.92917313,
         243.20994271, 243.68633428]],

       [[297.1899857 , 297.6237982 , 297.95503528, ..., 295.4505457 ,
         295.32998658, 295.05487915],
        [296.59005424, 297.09596253, 297.49915579, ..., 295.29059716,
         295.1700073 , 294.7989566 ],
        [295.76992812, 296.23054587, 296.65708274, ..., 295.15442138,
         295.00998537, 294.626334  ],
        ...,
        [252.39037715, 252.04962511, 251.65524335, ..., 241.72163807,
         242.61000973, 243.93278497],
        [249.06987326, 248.66822819, 248.21431545, ..., 242.12742803,
         242.79003593, 243.74867727],
        [247.43005818, 246.93209439, 246.37428385, ..., 242.84748108,
         243.38996739, 244.10871142]],

       [[297.04997563, 297.38785212, 297.63503348, ..., 296.09892817,
         295.98999483, 295.690696  ],
        [296.4100463 , 296.84401245, 297.17914422, ..., 295.82701626,
         295.79001767, 295.49075727],
        [295.62992871, 296.00626644, 296.35697279, ..., 295.59472609,
         295.56998294, 295.28282378],
        ...,
        [252.51039665, 252.14637887, 251.70761893, ..., 240.09173906,
         240.75006397, 241.87173824],
        [248.92985255, 248.55305942, 248.11071361, ..., 240.21550695,
         240.53002923, 241.23719787],
        [247.01007067, 246.58490681, 246.10268406, ..., 240.91155301,
         241.00997318, 241.45322238]]])
    • celsius
      (time, lat, lon)
      float64
      22.98 23.24 23.49 ... -32.14 -31.7
      array([[[ 22.98400285,  23.23669915,  23.48890434, ...,  23.32491403,
          23.28399523,  23.04925177],
        [ 22.82801481,  23.03275408,  23.27535111, ...,  22.94262952,
          22.92803004,  22.57099324],
        [ 22.89002377,  22.98556885,  23.15248584, ...,  22.62693524,
          22.58997807,  22.20693858],
        ...,
        [-28.10981478, -27.7891234 , -27.58903202, ..., -39.21370283,
         -37.63197058, -35.0719245 ],
        [-29.87008348, -29.37479887, -28.97624337, ..., -39.33408115,
         -37.80999757, -35.51757549],
        [-30.90996101, -30.27087087, -29.71224358, ..., -39.30207549,
         -37.73000183, -35.65357792]],

       [[ 23.10400254,  23.55204383,  23.88167095, ...,  22.91515567,
          22.88998873,  22.86773746],
        [ 23.06799591,  23.41768321,  23.67292138, ...,  22.5792619 ,
          22.5300323 ,  22.3638965 ],
        [ 23.08999633,  23.27058897,  23.41715262, ...,  22.35442901,
          22.26999514,  22.04133825],
        ...,
        [-27.62970937, -27.41290159, -27.29850427, ..., -41.50239881,
         -40.4719669 , -38.31965437],
        [-29.85004875, -29.5359456 , -29.29672901, ..., -41.3434626 ,
         -40.42996222, -38.63076015],
        [-30.4499802 , -30.11198963, -29.83273132, ..., -40.92743105,
         -39.99001614, -38.43074214]],

       [[ 23.16999207,  23.20234088,  23.22027682, ...,  23.54704484,
          23.44999087,  23.27994327],
        [ 23.08999633,  23.22072874,  23.27865721, ...,  23.24313408,
          23.05003657,  22.83448036],
        [ 22.9299744 ,  23.05135446,  23.09745435, ...,  23.02052488,
          22.70798618,  22.48218686],
        ...,
        [-26.22965149, -26.39704832, -26.64086611, ..., -41.96437258,
         -40.90995795, -38.53094857],
        [-29.01007373, -29.11959253, -29.25442578, ..., -41.36776822,
         -40.32987082, -38.24698168],
        [-29.92996985, -30.0132639 , -30.09123317, ..., -39.75164316,
         -38.69006184, -36.87086923]],

       ...,

       [[ 24.47998966,  25.10582762,  25.50503836, ...,  22.6286587 ,
          22.52000275,  22.35300373],
        [ 23.92005608,  24.56998781,  25.04915275, ...,  22.43671496,
          22.40000914,  22.0650933 ],
        [ 23.23995372,  23.83154769,  24.37425124, ...,  22.33205589,
          22.31999207,  21.90016761],
        ...,
        [-21.33958202, -21.42702704, -21.59008797, ..., -32.39286229,
         -31.77998965, -30.68542705],
        [-25.18016938, -25.27962571, -25.45424895, ..., -31.59692286,
         -31.21990373, -30.50374918],
        [-27.41991592, -27.61580626, -27.89428887, ..., -30.22082077,
         -29.94005118, -29.46365962]],

       [[ 24.0399918 ,  24.4738043 ,  24.80504138, ...,  22.3005518 ,
          22.17999269,  21.90488526],
        [ 23.44006035,  23.94596863,  24.34916189, ...,  22.14060326,
          22.02001341,  21.64896271],
        [ 22.61993422,  23.08055197,  23.50708884, ...,  22.00442749,
          21.85999148,  21.4763401 ],
        ...,
        [-20.75961675, -21.10036879, -21.49475055, ..., -31.42835583,
         -30.53998416, -29.21720893],
        [-24.08012063, -24.48176571, -24.93567845, ..., -31.02256587,
         -30.35995796, -29.40131662],
        [-25.71993572, -26.21789951, -26.77571005, ..., -30.30251281,
         -29.76002651, -29.04128248]],

       [[ 23.89998173,  24.23785823,  24.48503958, ...,  22.94893427,
          22.84000093,  22.5407021 ],
        [ 23.26005241,  23.69401855,  24.02915032, ...,  22.67702236,
          22.64002378,  22.34076337],
        [ 22.47993481,  22.85627254,  23.20697889, ...,  22.44473219,
          22.41998905,  22.13282989],
        ...,
        [-20.63959725, -21.00361502, -21.44237497, ..., -33.05825483,
         -32.39992993, -31.27825565],
        [-24.22014135, -24.59693448, -25.03928029, ..., -32.93448695,
         -32.61996466, -31.91279602],
        [-26.13992323, -26.56508709, -27.04730983, ..., -32.23844089,
         -32.14002072, -31.69677152]]])
    • slice
      (lat, lon)
      float64
      296.1 296.4 296.6 ... 235.4 237.5
      array([[296.13399675, 296.38669304, 296.63889823, ..., 296.47490793,
        296.43398913, 296.19924566],
       [295.97800871, 296.18274797, 296.42534501, ..., 296.09262341,
        296.07802394, 295.72098714],
       [296.04001766, 296.13556275, 296.30247974, ..., 295.77692914,
        295.73997197, 295.35693248],
       ...,
       [245.04017912, 245.36087049, 245.56096188, ..., 233.93629106,
        235.51802332, 238.0780694 ],
       [243.27991042, 243.77519503, 244.17375053, ..., 233.81591274,
        235.33999633, 237.63241841],
       [242.24003289, 242.87912303, 243.43775032, ..., 233.84791841,
        235.41999207, 237.49641598]])
  • regrid_method :
    bilinear
[6]:

# verify that the result is the same as regridding each variable one-by-one
for k in ds.data_vars:
    print(k, ds_out[k].equals(regridder(ds[k])))

air True
celsius True
slice True

Invalid dimension orderings to avoid

xESMF assumes the horizontal dimensions are the last/rightmost dimensions, which matches the convention of most NetCDF data.

[7]:

# xESMF doesn't like horizontal dimensions to be the first/leftmost dimensions
ds_bad = ds.copy()
ds_bad["air"] = ds_bad["air"].transpose()
ds_bad

[7]:
Show/Hide data repr Show/Hide attributes
xarray.Dataset
    • lat: 25
    • lon: 53
    • time: 2920
    • lat
      (lat)
      float32
      75.0 72.5 70.0 ... 20.0 17.5 15.0
      standard_name :
      latitude
      long_name :
      Latitude
      units :
      degrees_north
      axis :
      Y
      array([75. , 72.5, 70. , 67.5, 65. , 62.5, 60. , 57.5, 55. , 52.5, 50. , 47.5,
       45. , 42.5, 40. , 37.5, 35. , 32.5, 30. , 27.5, 25. , 22.5, 20. , 17.5,
       15. ], dtype=float32)
    • lon
      (lon)
      float32
      200.0 202.5 205.0 ... 327.5 330.0
      standard_name :
      longitude
      long_name :
      Longitude
      units :
      degrees_east
      axis :
      X
      array([200. , 202.5, 205. , 207.5, 210. , 212.5, 215. , 217.5, 220. , 222.5,
       225. , 227.5, 230. , 232.5, 235. , 237.5, 240. , 242.5, 245. , 247.5,
       250. , 252.5, 255. , 257.5, 260. , 262.5, 265. , 267.5, 270. , 272.5,
       275. , 277.5, 280. , 282.5, 285. , 287.5, 290. , 292.5, 295. , 297.5,
       300. , 302.5, 305. , 307.5, 310. , 312.5, 315. , 317.5, 320. , 322.5,
       325. , 327.5, 330. ], dtype=float32)
    • time
      (time)
      datetime64[ns]
      2013-01-01 ... 2014-12-31T18:00:00
      standard_name :
      time
      long_name :
      Time
      array(['2013-01-01T00:00:00.000000000', '2013-01-01T06:00:00.000000000',
       '2013-01-01T12:00:00.000000000', ..., '2014-12-31T06:00:00.000000000',
       '2014-12-31T12:00:00.000000000', '2014-12-31T18:00:00.000000000'],
      dtype='datetime64[ns]')
    • air
      (lon, lat, time)
      float32
      241.2 242.09999 ... 295.19 295.69
      long_name :
      4xDaily Air temperature at sigma level 995
      units :
      degK
      precision :
      2
      GRIB_id :
      11
      GRIB_name :
      TMP
      var_desc :
      Air temperature
      dataset :
      NMC Reanalysis
      level_desc :
      Surface
      statistic :
      Individual Obs
      parent_stat :
      Other
      actual_range :
      [185.16 322.1 ]
      array([[[241.2    , 242.09999, 242.29999, ..., 243.48999, 245.79   ,
         245.09   ],
        [243.79999, 243.59999, 244.59999, ..., 249.09   , 249.89   ,
         249.89   ],
        [250.     , 253.2    , 256.19998, ..., 262.69   , 262.38998,
         262.99   ],
        ...,
        [296.6    , 296.4    , 295.6    , ..., 294.79   , 293.69   ,
         293.79   ],
        [295.9    , 296.19998, 296.19998, ..., 296.79   , 296.29   ,
         296.09   ],
        [296.29   , 296.29   , 296.4    , ..., 298.19   , 297.79   ,
         297.69   ]],

       [[242.5    , 242.7    , 242.2    , ..., 242.98999, 244.79   ,
         244.29   ],
        [244.5    , 244.09999, 244.39   , ..., 248.98999, 249.29   ,
         249.29   ],
        [249.79999, 252.89   , 255.5    , ..., 262.19   , 261.79   ,
         262.19   ],
        ...,
        [296.19998, 295.9    , 295.4    , ..., 295.29   , 293.88998,
         293.69   ],
        [296.19998, 296.69998, 296.5    , ..., 297.88998, 297.19   ,
         296.88998],
        [296.79   , 297.19998, 296.29   , ..., 299.19   , 298.38998,
         298.09   ]],

       [[243.5    , 243.09999, 242.29999, ..., 242.09   , 243.48999,
         243.29   ],
        [244.7    , 244.2    , 244.     , ..., 248.59   , 248.48999,
         248.39   ],
        [248.89   , 252.09999, 254.2    , ..., 261.69   , 261.29   ,
         261.38998],
        ...,
        [296.4    , 296.19998, 295.4    , ..., 297.49   , 295.38998,
         295.09   ],
        [296.79   , 296.79   , 296.29   , ..., 298.29   , 297.59   ,
         297.19   ],
        [297.1    , 297.4    , 296.4    , ..., 298.79   , 298.49   ,
         298.09   ]],

       ...,

       [[232.79999, 232.     , 234.29999, ..., 244.18999, 243.29   ,
         241.68999],
        [232.79999, 231.     , 230.29999, ..., 240.59   , 241.29   ,
         239.59   ],
        [233.2    , 230.79999, 231.2    , ..., 239.39   , 240.48999,
         239.89   ],
        ...,
        [295.4    , 295.4    , 296.29   , ..., 295.49   , 295.09   ,
         295.29   ],
        [295.9    , 295.6    , 296.4    , ..., 295.49   , 295.29   ,
         295.69   ],
        [296.9    , 296.4    , 297.     , ..., 296.09   , 295.69   ,
         296.49   ]],

       [[235.5    , 233.59999, 236.09999, ..., 244.48999, 243.98999,
         241.48999],
        [235.29999, 232.5    , 232.     , ..., 241.29   , 242.48999,
         240.29   ],
        [236.39   , 233.39   , 233.2    , ..., 241.68999, 243.09   ,
         242.59   ],
        ...,
        [295.1    , 295.1    , 295.29   , ..., 295.38998, 294.69   ,
         295.09   ],
        [295.9    , 295.5    , 296.     , ..., 295.49   , 295.09   ,
         295.69   ],
        [296.79   , 296.4    , 297.     , ..., 295.79   , 295.49   ,
         296.19   ]],

       [[238.59999, 235.79999, 238.7    , ..., 244.89   , 244.79   ,
         241.79   ],
        [239.29999, 235.7    , 235.7    , ..., 242.68999, 244.29   ,
         241.68999],
        [241.7    , 238.5    , 238.2    , ..., 245.18999, 246.89   ,
         246.29   ],
        ...,
        [294.69998, 294.79   , 295.     , ..., 294.69   , 294.29   ,
         294.69   ],
        [295.19998, 295.1    , 295.6    , ..., 294.79   , 294.38998,
         295.19   ],
        [296.6    , 296.6    , 296.79   , ..., 295.79   , 295.19   ,
         295.69   ]]], dtype=float32)
    • celsius
      (time, lat, lon)
      float32
      -31.949997 -30.649994 ... 22.540009
      array([[[-31.949997, -30.649994, -29.649994, ..., -40.350006,
         -37.649994, -34.550003],
        [-29.350006, -28.649994, -28.449997, ..., -40.350006,
         -37.850006, -33.850006],
        [-23.149994, -23.350006, -24.259995, ..., -39.949997,
         -36.759995, -31.449997],
        ...,
        [ 23.450012,  23.049988,  23.25    , ...,  22.25    ,
          21.950012,  21.549988],
        [ 22.75    ,  23.049988,  23.640015, ...,  22.75    ,
          22.75    ,  22.049988],
        [ 23.140015,  23.640015,  23.950012, ...,  23.75    ,
          23.640015,  23.450012]],

       [[-31.050003, -30.449997, -30.050003, ..., -41.149994,
         -39.550003, -37.350006],
        [-29.550003, -29.050003, -28.949997, ..., -42.149994,
         -40.649994, -37.449997],
        [-19.949997, -20.259995, -21.050003, ..., -42.350006,
         -39.759995, -34.649994],
        ...,
        [ 23.25    ,  22.75    ,  23.049988, ...,  22.25    ,
          21.950012,  21.640015],
        [ 23.049988,  23.549988,  23.640015, ...,  22.450012,
          22.350006,  21.950012],
        [ 23.140015,  24.049988,  24.25    , ...,  23.25    ,
          23.25    ,  23.450012]],

       [[-30.850006, -30.949997, -30.850006, ..., -38.850006,
         -37.050003, -34.449997],
        [-28.550003, -28.759995, -29.149994, ..., -42.850006,
         -41.149994, -37.449997],
        [-16.950012, -17.649994, -18.949997, ..., -41.949997,
         -39.949997, -34.949997],
        ...,
        [ 22.450012,  22.25    ,  22.25    , ...,  23.140015,
          22.140015,  21.850006],
        [ 23.049988,  23.350006,  23.140015, ...,  23.25    ,
          22.850006,  22.450012],
        [ 23.25    ,  23.140015,  23.25    , ...,  23.850006,
          23.850006,  23.640015]],

       ...,

       [[-29.660004, -30.160004, -31.059998, ..., -28.960007,
         -28.660004, -28.259995],
        [-24.059998, -24.160004, -24.559998, ..., -32.559998,
         -31.86    , -30.460007],
        [-10.459991, -10.959991, -11.459991, ..., -33.759995,
         -31.460007, -27.960007],
        ...,
        [ 21.640015,  22.140015,  24.339996, ...,  22.339996,
          22.23999 ,  21.540009],
        [ 23.640015,  24.73999 ,  25.140015, ...,  22.339996,
          22.339996,  21.640015],
        [ 25.040009,  26.040009,  25.640015, ...,  22.940002,
          22.640015,  22.640015]],

       [[-27.36    , -28.36    , -29.660004, ..., -29.86    ,
         -29.160004, -28.36    ],
        [-23.259995, -23.86    , -24.660004, ..., -31.86    ,
         -30.660004, -28.86    ],
        [-10.76001 , -11.359985, -11.859985, ..., -32.660004,
         -30.059998, -26.259995],
        ...,
        [ 20.540009,  20.73999 ,  22.23999 , ...,  21.940002,
          21.540009,  21.140015],
        [ 23.140015,  24.040009,  24.440002, ...,  22.140015,
          21.940002,  21.23999 ],
        [ 24.640015,  25.23999 ,  25.339996, ...,  22.540009,
          22.339996,  22.040009]],

       [[-28.059998, -28.86    , -29.86    , ..., -31.460007,
         -31.660004, -31.36    ],
        [-23.259995, -23.86    , -24.759995, ..., -33.559998,
         -32.86    , -31.460007],
        [-10.160004, -10.959991, -11.76001 , ..., -33.259995,
         -30.559998, -26.86    ],
        ...,
        [ 20.640015,  20.540009,  21.940002, ...,  22.140015,
          21.940002,  21.540009],
        [ 22.940002,  23.73999 ,  24.040009, ...,  22.540009,
          22.540009,  22.040009],
        [ 24.540009,  24.940002,  24.940002, ...,  23.339996,
          23.040009,  22.540009]]], dtype=float32)
    • slice
      (lat, lon)
      float32
      241.2 242.5 243.5 ... 296.79 296.6
      long_name :
      4xDaily Air temperature at sigma level 995
      units :
      degK
      precision :
      2
      GRIB_id :
      11
      GRIB_name :
      TMP
      var_desc :
      Air temperature
      dataset :
      NMC Reanalysis
      level_desc :
      Surface
      statistic :
      Individual Obs
      parent_stat :
      Other
      actual_range :
      [185.16 322.1 ]
      array([[241.2    , 242.5    , 243.5    , ..., 232.79999, 235.5    , 238.59999],
       [243.79999, 244.5    , 244.7    , ..., 232.79999, 235.29999, 239.29999],
       [250.     , 249.79999, 248.89   , ..., 233.2    , 236.39   , 241.7    ],
       ...,
       [296.6    , 296.19998, 296.4    , ..., 295.4    , 295.1    , 294.69998],
       [295.9    , 296.19998, 296.79   , ..., 295.9    , 295.9    , 295.19998],
       [296.29   , 296.79   , 297.1    , ..., 296.9    , 296.79   , 296.6    ]],
      dtype=float32)
  • Conventions :
    COARDS
    title :
    4x daily NMC reanalysis (1948)
    description :
    Data is from NMC initialized reanalysis (4x/day). These are the 0.9950 sigma level values.
    platform :
    Model
    references :
    http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html
[8]:

# regridder(ds_bad)  # comment this line to see the error message

[9]:

# besides ordering dimensions properly, another simple fix is to drop bad variables
regridder(ds_bad.drop("air"))

using dimensions ('lat', 'lon') from data variable celsius as the horizontal dimensions for this dataset.

[9]:
Show/Hide data repr Show/Hide attributes
xarray.Dataset
    • lat: 59
    • lon: 87
    • time: 2920
    • time
      (time)
      datetime64[ns]
      2013-01-01 ... 2014-12-31T18:00:00
      standard_name :
      time
      long_name :
      Time
      array(['2013-01-01T00:00:00.000000000', '2013-01-01T06:00:00.000000000',
       '2013-01-01T12:00:00.000000000', ..., '2014-12-31T06:00:00.000000000',
       '2014-12-31T12:00:00.000000000', '2014-12-31T18:00:00.000000000'],
      dtype='datetime64[ns]')
    • lon
      (lon)
      float64
      200.0 201.5 203.0 ... 327.5 329.0
      array([200. , 201.5, 203. , 204.5, 206. , 207.5, 209. , 210.5, 212. , 213.5,
       215. , 216.5, 218. , 219.5, 221. , 222.5, 224. , 225.5, 227. , 228.5,
       230. , 231.5, 233. , 234.5, 236. , 237.5, 239. , 240.5, 242. , 243.5,
       245. , 246.5, 248. , 249.5, 251. , 252.5, 254. , 255.5, 257. , 258.5,
       260. , 261.5, 263. , 264.5, 266. , 267.5, 269. , 270.5, 272. , 273.5,
       275. , 276.5, 278. , 279.5, 281. , 282.5, 284. , 285.5, 287. , 288.5,
       290. , 291.5, 293. , 294.5, 296. , 297.5, 299. , 300.5, 302. , 303.5,
       305. , 306.5, 308. , 309.5, 311. , 312.5, 314. , 315.5, 317. , 318.5,
       320. , 321.5, 323. , 324.5, 326. , 327.5, 329. ])
    • lat
      (lat)
      float64
      16.0 17.0 18.0 ... 72.0 73.0 74.0
      array([16., 17., 18., 19., 20., 21., 22., 23., 24., 25., 26., 27., 28., 29.,
       30., 31., 32., 33., 34., 35., 36., 37., 38., 39., 40., 41., 42., 43.,
       44., 45., 46., 47., 48., 49., 50., 51., 52., 53., 54., 55., 56., 57.,
       58., 59., 60., 61., 62., 63., 64., 65., 66., 67., 68., 69., 70., 71.,
       72., 73., 74.])
    • celsius
      (time, lat, lon)
      float64
      22.98 23.24 23.49 ... -32.14 -31.7
      array([[[ 22.98400285,  23.23669915,  23.48890434, ...,  23.32491403,
          23.28399523,  23.04925177],
        [ 22.82801481,  23.03275408,  23.27535111, ...,  22.94262952,
          22.92803004,  22.57099324],
        [ 22.89002377,  22.98556885,  23.15248584, ...,  22.62693524,
          22.58997807,  22.20693858],
        ...,
        [-28.10981478, -27.7891234 , -27.58903202, ..., -39.21370283,
         -37.63197058, -35.0719245 ],
        [-29.87008348, -29.37479887, -28.97624337, ..., -39.33408115,
         -37.80999757, -35.51757549],
        [-30.90996101, -30.27087087, -29.71224358, ..., -39.30207549,
         -37.73000183, -35.65357792]],

       [[ 23.10400254,  23.55204383,  23.88167095, ...,  22.91515567,
          22.88998873,  22.86773746],
        [ 23.06799591,  23.41768321,  23.67292138, ...,  22.5792619 ,
          22.5300323 ,  22.3638965 ],
        [ 23.08999633,  23.27058897,  23.41715262, ...,  22.35442901,
          22.26999514,  22.04133825],
        ...,
        [-27.62970937, -27.41290159, -27.29850427, ..., -41.50239881,
         -40.4719669 , -38.31965437],
        [-29.85004875, -29.5359456 , -29.29672901, ..., -41.3434626 ,
         -40.42996222, -38.63076015],
        [-30.4499802 , -30.11198963, -29.83273132, ..., -40.92743105,
         -39.99001614, -38.43074214]],

       [[ 23.16999207,  23.20234088,  23.22027682, ...,  23.54704484,
          23.44999087,  23.27994327],
        [ 23.08999633,  23.22072874,  23.27865721, ...,  23.24313408,
          23.05003657,  22.83448036],
        [ 22.9299744 ,  23.05135446,  23.09745435, ...,  23.02052488,
          22.70798618,  22.48218686],
        ...,
        [-26.22965149, -26.39704832, -26.64086611, ..., -41.96437258,
         -40.90995795, -38.53094857],
        [-29.01007373, -29.11959253, -29.25442578, ..., -41.36776822,
         -40.32987082, -38.24698168],
        [-29.92996985, -30.0132639 , -30.09123317, ..., -39.75164316,
         -38.69006184, -36.87086923]],

       ...,

       [[ 24.47998966,  25.10582762,  25.50503836, ...,  22.6286587 ,
          22.52000275,  22.35300373],
        [ 23.92005608,  24.56998781,  25.04915275, ...,  22.43671496,
          22.40000914,  22.0650933 ],
        [ 23.23995372,  23.83154769,  24.37425124, ...,  22.33205589,
          22.31999207,  21.90016761],
        ...,
        [-21.33958202, -21.42702704, -21.59008797, ..., -32.39286229,
         -31.77998965, -30.68542705],
        [-25.18016938, -25.27962571, -25.45424895, ..., -31.59692286,
         -31.21990373, -30.50374918],
        [-27.41991592, -27.61580626, -27.89428887, ..., -30.22082077,
         -29.94005118, -29.46365962]],

       [[ 24.0399918 ,  24.4738043 ,  24.80504138, ...,  22.3005518 ,
          22.17999269,  21.90488526],
        [ 23.44006035,  23.94596863,  24.34916189, ...,  22.14060326,
          22.02001341,  21.64896271],
        [ 22.61993422,  23.08055197,  23.50708884, ...,  22.00442749,
          21.85999148,  21.4763401 ],
        ...,
        [-20.75961675, -21.10036879, -21.49475055, ..., -31.42835583,
         -30.53998416, -29.21720893],
        [-24.08012063, -24.48176571, -24.93567845, ..., -31.02256587,
         -30.35995796, -29.40131662],
        [-25.71993572, -26.21789951, -26.77571005, ..., -30.30251281,
         -29.76002651, -29.04128248]],

       [[ 23.89998173,  24.23785823,  24.48503958, ...,  22.94893427,
          22.84000093,  22.5407021 ],
        [ 23.26005241,  23.69401855,  24.02915032, ...,  22.67702236,
          22.64002378,  22.34076337],
        [ 22.47993481,  22.85627254,  23.20697889, ...,  22.44473219,
          22.41998905,  22.13282989],
        ...,
        [-20.63959725, -21.00361502, -21.44237497, ..., -33.05825483,
         -32.39992993, -31.27825565],
        [-24.22014135, -24.59693448, -25.03928029, ..., -32.93448695,
         -32.61996466, -31.91279602],
        [-26.13992323, -26.56508709, -27.04730983, ..., -32.23844089,
         -32.14002072, -31.69677152]]])
    • slice
      (lat, lon)
      float64
      296.1 296.4 296.6 ... 235.4 237.5
      array([[296.13399675, 296.38669304, 296.63889823, ..., 296.47490793,
        296.43398913, 296.19924566],
       [295.97800871, 296.18274797, 296.42534501, ..., 296.09262341,
        296.07802394, 295.72098714],
       [296.04001766, 296.13556275, 296.30247974, ..., 295.77692914,
        295.73997197, 295.35693248],
       ...,
       [245.04017912, 245.36087049, 245.56096188, ..., 233.93629106,
        235.51802332, 238.0780694 ],
       [243.27991042, 243.77519503, 244.17375053, ..., 233.81591274,
        235.33999633, 237.63241841],
       [242.24003289, 242.87912303, 243.43775032, ..., 233.84791841,
        235.41999207, 237.49641598]])
  • regrid_method :
    bilinear