How can I attribute and cite ECMWF data?

ECMWF is committed to providing open data under the Creative Commons Attribution (CC-BY-4.0) licence. This licence allows users to copy, share, adapt, and build on ECMWF data — including for commercial purposes — provided appropriate credit is given.

Attribution is not just a formality. It:

• Ensures that ECMWF is properly recognised for its data and services,

• Helps users of your work understand where the data produced,

• Distinguishes between the creator of the data (ECMWF) and the source/service or platform delivering it (e.g. a cloud provider).

In order to continue receiving public funding, ECMWF needs to demonstrate the application. Your attribution helps us to highlight our role in the general community and push for continued free provision.

1. What to Include in an Attribution

When citing or attributing ECMWF data, please include:

1. ECMWF as the data producer/creator

2. Dataset name/description

3. Source (where you obtained/accessed the data) or service provider (if not directly from ECMWF)

4. Licence reference (CC-BY-4.0) and whether the original data has been modified

These are legal requirements of the CC-BY-4.0 licence and should be adopted wherever ECMWF products are used in services or graphics.

2. Example Attributions

• Direct from ECMWF
  “ECMWF IFS Forecast data, accessed from ECMWF’s MARS archive, © European Centre for Medium-Range Weather Forecasts (ECMWF), 2025. Licensed under CC-BY-4.0.”

• Via a Cloud or Third-Party Service
  “ECMWF IFS Forecast data, © European Centre for Medium-Range Weather Forecasts (ECMWF), 2025, accessed via Amazon Web Services. Licensed under CC-BY-4.0.”

• Combined Sources
  “ECMWF Reanalysis data (ERA5), © European Centre for Medium-Range Weather Forecasts (ECMWF), 2025, retrieved via the Copernicus Climate Data Store. Licensed under CC-BY-4.0.”

  • In instances where there are many sources being consistently used, you may link to a page/document where there are list of all the sources.

• Modification to ECMWF data

• "Products based on ECMWF..." or "Modified from ECMWF products..."

3. Publications and Academic Use

For academic papers, please use a formal citation where possible. ECMWF datasets are often assigned DOIs, which should be included in your reference list. Example:

Hersbach, H., et al. (2020). The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society, 146(730), 1999–2049. https://doi.org/10.1002/qj.3803

Note that for those receiving data under our fee-waiver scheme for Research Project purposes, an acknowledgement example is provided also: 

ECMWF data received with thanks under the fee-waiver scheme for this research. 

4. Use of the ECMWF Logo

• The ECMWF logo may be used to support attribution where it benefits ECMWF in publications, websites, or promotional material, however approval is required to ensure correct use.
• Attribution should always be in text form (“© European Centre for Medium-Range Weather Forecasts (ECMWF)”).

5. Good Practice

• Be clear whether you are citing the data producer/creator (ECMWF) or the source (where you obtained/accessed it) platform/service provider (e.g. AWS, DIAS, Copernicus). Both should be mentioned where relevant.

• Always state the licence: CC-BY-4.0.

• If combining ECMWF data with other datasets, ensure that all licences are respected and cited appropriately.