Calculate Monthly Means

This notebook demonstrates how to calculate the monthly mean 2m temperature for ERA5 data using earthkit-data and earthkit-transforms. Monthly means are common for climate summaries and reporting.

from earthkit import data as ekd
from earthkit import transforms as ekt
from earthkit.transforms._tools import earthkit_remote_test_data_file

remote_era5_file = earthkit_remote_test_data_file("era5-Europe-sfc-2m-temperature-3deg-2015-2017.grib")
era5_data = ekd.from_source("url", remote_era5_file)
ds = era5_data.to_xarray()

# Calculate monthly mean
monthly_mean = ekt.temporal.monthly_mean(ds)

monthly_mean

<xarray.Dataset> Size: 159kB
Dimensions:                  (forecast_reference_time: 36, latitude: 19,
                              longitude: 29)
Coordinates:
  * forecast_reference_time  (forecast_reference_time) datetime64[us] 288B 20...
  * latitude                 (latitude) float64 152B 79.0 76.0 ... 28.0 25.0
  * longitude                (longitude) float64 232B -25.0 -22.0 ... 56.0 59.0
Data variables:
    2t                       (forecast_reference_time, latitude, longitude) float64 159kB ...
Attributes:
    Conventions:  CF-1.8
    institution:  ECMWF

xarray.Dataset

• Dimensions:
  • forecast_reference_time: 36
  • latitude: 19
  • longitude: 29
• Coordinates: (3)
  • forecast_reference_time
    (forecast_reference_time)
    datetime64[us]
    2015-01-01 ... 2017-12-01

    standard_name :

    forecast_reference_time

    long_name :

    initial time of forecast

    array(['2015-01-01T00:00:00.000000', '2015-02-01T00:00:00.000000',
           '2015-03-01T00:00:00.000000', '2015-04-01T00:00:00.000000',
           '2015-05-01T00:00:00.000000', '2015-06-01T00:00:00.000000',
           '2015-07-01T00:00:00.000000', '2015-08-01T00:00:00.000000',
           '2015-09-01T00:00:00.000000', '2015-10-01T00:00:00.000000',
           '2015-11-01T00:00:00.000000', '2015-12-01T00:00:00.000000',
           '2016-01-01T00:00:00.000000', '2016-02-01T00:00:00.000000',
           '2016-03-01T00:00:00.000000', '2016-04-01T00:00:00.000000',
           '2016-05-01T00:00:00.000000', '2016-06-01T00:00:00.000000',
           '2016-07-01T00:00:00.000000', '2016-08-01T00:00:00.000000',
           '2016-09-01T00:00:00.000000', '2016-10-01T00:00:00.000000',
           '2016-11-01T00:00:00.000000', '2016-12-01T00:00:00.000000',
           '2017-01-01T00:00:00.000000', '2017-02-01T00:00:00.000000',
           '2017-03-01T00:00:00.000000', '2017-04-01T00:00:00.000000',
           '2017-05-01T00:00:00.000000', '2017-06-01T00:00:00.000000',
           '2017-07-01T00:00:00.000000', '2017-08-01T00:00:00.000000',
           '2017-09-01T00:00:00.000000', '2017-10-01T00:00:00.000000',
           '2017-11-01T00:00:00.000000', '2017-12-01T00:00:00.000000'],
          dtype='datetime64[us]')

  • latitude
    (latitude)
    float64
    79.0 76.0 73.0 ... 31.0 28.0 25.0

    units :

    degrees_north

    standard_name :

    latitude

    long_name :

    latitude

    array([79., 76., 73., 70., 67., 64., 61., 58., 55., 52., 49., 46., 43., 40.,
           37., 34., 31., 28., 25.])

  • longitude
    (longitude)
    float64
    -25.0 -22.0 -19.0 ... 56.0 59.0

    units :

    degrees_east

    standard_name :

    longitude

    long_name :

    longitude

    array([-25., -22., -19., -16., -13., -10.,  -7.,  -4.,  -1.,   2.,   5.,   8.,
            11.,  14.,  17.,  20.,  23.,  26.,  29.,  32.,  35.,  38.,  41.,  44.,
            47.,  50.,  53.,  56.,  59.])

• Data variables: (1)
  • 2t
    (forecast_reference_time, latitude, longitude)
    float64
    247.7 251.5 255.9 ... 293.8 295.6

    standard_name :

    unknown

    long_name :

    2 metre temperature

    units :

    kelvin

    level_type :

    surface

    _earthkit :

    {"message": {"__bytes_b64__": "R1JJQgAAbAEAADSAYv//gKcBAAAPAQEAAAEAAAAAAAAVAAAAAAAAAAAAAAAAAAAAARcCBAEwMDAxAAAAAAAgAP8AAB0AEwE0mIBhqIAAYagA5ngLuAu4AAAAAAAAAAwAgAJEuX1uAAA3Nzc3"}, "bitsPerValue": 16, "grid_spec": {"area": [79, -25, 25, 59], "grid": [3, 3], "reference": [2, 1]}}

    array([[[247.65598039, 251.50549526, 255.9272285 , ..., 253.25700735,
             253.09163752, 252.97906506],
            [249.74996665, 252.78064962, 259.59965478, ..., 263.67075483,
             262.28099614, 259.59069246],
            [252.82988727, 259.70375319, 262.62172194, ..., 250.98544422,
             247.5842503 , 248.86088525],
            ...,
            [290.96981922, 290.61483875, 290.42981166, ..., 278.38435425,
             281.19376706, 287.17773253],
            [291.79725118, 291.58083233, 291.36876075, ..., 287.07037366,
             286.60162366, 286.99398127],
            [292.8054102 , 292.24432779, 291.60713651, ..., 293.23382187,
             292.99075231, 294.93530876]],
    
           [[241.06330068, 244.75800283, 249.55634267, ..., 255.8178696 ,
             255.23561164, 254.59196976],
            [242.30636011, 245.06438187, 251.43493502, ..., 263.79096181,
             260.30231435, 256.81663145],
            [244.0642598 , 250.71894033, 254.53388173, ..., 255.70889568,
             251.04629803, 253.67054817],
    ...
            [294.48119876, 294.46165123, 294.24568443, ..., 282.95351321,
             286.33502363, 292.36199303],
            [295.36083743, 295.14055748, 295.14962324, ..., 293.18751386,
             291.3244442 , 293.26925214],
            [296.25115318, 296.30678469, 295.85663821, ..., 300.40359459,
             298.50427818, 299.28132896]],
    
           [[248.26696261, 253.35909025, 255.76883698, ..., 264.88504791,
             264.0769897 , 263.14027725],
            [249.74302107, 252.63290578, 257.00664569, ..., 270.04840162,
             268.90267329, 265.84867883],
            [250.07642266, 254.81635777, 257.37373869, ..., 266.14245089,
             262.2731055 , 266.71887478],
            ...,
            [293.39114355, 292.99524197, 292.60510525, ..., 279.26948277,
             281.84967115, 285.86964343],
            [294.1059243 , 293.73898881, 293.28833672, ..., 289.21591359,
             286.69283836, 287.56779111],
            [294.9497373 , 294.47265502, 293.68546689, ..., 295.61340603,
             293.75798453, 295.57141384]]], shape=(36, 19, 29))

• Attributes: (2)

  Conventions :

  CF-1.8

  institution :

  ECMWF