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This dataset presented here is a subset of some parameters of the full CDS ERA5 single levels hourly dataset on 0.25 degrees resolution and is stored in Analysis Ready Cloud Optimised (ARCO) format, which has been implemented for retrieving long time-series for a single point in a efficient way. It is this source of ERA5 data that is used by the ERA-Explorer to ensure response times required for the interactive web-application.

Methodology

Excerpt

The process to generate this dataset involves:

  • Fetching ERA5 data in GRIB format.
  • Apply homogenization conventions, as applicable
    • Rename spatial coordinates to latitude, longitude
    • Ensure latitude, longitude ranges are between [-90, +90], [-180, +180]
    • In the accumulation variables (e.g. Total precipitation), time is expressed in one single dimension called time which in ERA5 netCDFs is usually called valid_time.
    • In the accumulation variables, if the number of hourly samples is incomplete (less than 24) the date is skipped (e.g. 1940-01-01).
    • Drop "number", "step", "surface" and "valid_time".
  • Written to an ARCO Zarr archive (which is similar in structure to netCDF)
  • The CDS requests the data from the Zarr archive using xarray and writes the data to netCDF or CSV (as requested).

Data organization and access

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NameUnitsVariable nameNotes
1

10 metre U wind component

m s-110m_u_component_of_wind
210 metre V wind componentm s-110m_v_component_of_wind
310 metre U wind componentm s-1100m_u_component_of_wind
4100 metre V wind componentm s-1100m_v_component_of_wind
52 metre dewpoint temperatureK2m_dewpoint_temperature
62 metre temperatureK2m_temperature
7Boundary layer heightmboundary_layer_height
8Cloud base heightmcloud_base_height
9Mean sea level pressurePamean_sea_level_pressure
10Sea surface temperatureKsea_surface_temperatureSea surface temperature is available at the usual times, eg hourly, but its content is only updated once daily.
11Skin TemperatureKskin_temperature 
12Surface pressurePasurface_pressure
13Surface solar radiation downwardsJ m**-2surface_solar_radiation_downwards
14Surface thermal radiation downwardsJ m**-2surface_thermal_radiation_downwards
15Total cloud cover(0 - 1)total_cloud_cover
16Total precipitationmtotal_precipitation
17

J m**-2

total_sky_direct_solar_radiation_at_surface


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CountNameUnitsVariable name

1

Mean wave directionDegreesmean_wave_direction
2Mean wave periodsmean_wave_period
3Significant height of combined wind waves and swellmsignificant_height_of_combined_wind_waves_and_swell

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