ERA5

ERA5 is the fifth-generation ECMWF atmospheric reanalysis of the global climate, produced by the Copernicus Climate Change Service (C3S). It covers the period from January 1940 to present and provides hourly estimates of a wide range of atmospheric, land, and oceanic variables. ERA5 is available on a 30 km grid and is available up to heihgt of 80 km. ERA5 includes uncertainty estimates at reduced spatial and temporal resolutions and is available in three main dataset.

Available Datasets

1. ERA5 Hourly Data on Single Levels

Provides surface and near-surface variables (e.g., temperature at 2 m, surface pressure, total precipitation).

• Grid resolution: cca. 30 km (0,25° x 0,25° grid)
• Vertical levels: Single level (surface)
• Coverage: near-surface
• Dataset on ECMWF website
• STAC: https://stac.cesnet.cz/collections/reanalysis-era5-single-levels
• Variables list

2. ERA5 Hourly Data on Pressure Levels

Provides data on standard atmospheric pressure levels (e.g., temperature, wind, humidity).

• Grid resolution: cca. 30 km (0,25° x 0,25° grid)
• Coverage: vertical on pressure levels from 1 hPa to 1 000 hPa
• Dataset on ECMWF website
• STAC: https://stac.cesnet.cz/collections/reanalysis-era5-pressure-levels
• Variables list

3. ERA5-Land

A land-surface-focused dataset providing improved resolution and accuracy over land areas by re-running the ERA5 land component. It contains quanitites such as soil moisture & temperature, snow depth, evaporation, runoff, etc.

• Grid resolution: cca. 9 km (0,1° x 0,1° grid)
• Coverage: Land surfaces only
• Temporal coverage: From January 1950 to present
• Dataset on ECMWF website
• STAC: https://stac.cesnet.cz/collections/reanalysis-era5-land

Data Redistribution

Redistributed ECMWF datasets are available for the Czech Republic national teritory and border areas of neighboring countries, covering the bounding box 48.48, 12.07, 51.08, 19.00.

As of April 11, 2024, data from January 2020 to May 2024 has been downloaded, with newer as well as older data still being downloaded and processed back to the earliest available month of each respective dataset.

Data Availability and Update Policy

Each dataset is provided as complete monthly .grib files, organized in STAC catalog by collection and item in hierarchical structure:

/collections/<dataset-name>/items/YYYY-MM-<dataset-name>

NetCDF format is as of today considered experimental by ECMWF and thus it is not being currently downloaded. hrefs to these files are set as null!

Datasets for reanalysis on single levels and pressure levels includes four product types:

• Reanalysis
• Ensemble mean
• Ensemble members
• Ensemble spread

ERA-5 land includes only Reanalysis product type.

According to ECMWF documentation, ERA5 data can be re-processed retrospectively for up to three months. Therefore:

• New monthly data is downloaded up to the end of the previous month.
• Finalized data is re-downloaded for the four months prior, typically after the 2nd day of the current month.

For example, in November, data from October is added, and finalized data for July is refreshed.

Downloading Data

Each STAC API item returns a GeoJSON with an assets node, containing direct .grib links for each product type:

"assets": {
"reanalysis-grib": { "href": "..." },
"ensemble-mean-grib": { "href": "..." },
"ensemble-members-grib": { "href": "..." },
"ensemble-spread-grib": { "href": "..." },
"reanalysis-netcdf": { "href": null },
"ensemble-mean-netcdf": { "href": null },
"ensemble-members-netcdf": { "href": null },
"ensemble-spread-netcdf": { "href": null }
}

License

The data is available under the License to use Copernicus Products.