ECMWF releases a much larger open dataset

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ECMWF now provides a much larger open dataset to the public, representing weather forecasts at a higher resolution and a reduction in some release times, after a first set of data was made available in early 2022.

The changes can be summarised as follows:

  • Medium-range data of the Integrated Forecasting System (IFS) are provided at a resolution of 0.25 x 0.25 degrees (28 x 28 km), compared to 0.4 x 0.4 degrees before, and some additional parameters will be added.
  • Medium-range data of the latest beta version of the Artificial Intelligence/Integrated Forecasting System (AIFS) are also available at a resolution of 0.25 x 0.25 degrees.
  • ECMWF’s contribution to the sub-seasonal to seasonal (S2S) dataset, which is part of a global scheme, is now available with a 48-hour delay rather than the previous three-week delay.
  • All parameters of the EU’s Copernicus Atmosphere Monitoring Service (CAMS) that used to a have a six-day embargo are now available in real time.

An overview of open data is given on the ECMWF website.

Change in resolution and more parameters

IFS medium-range data are now provided at a finer spatial resolution than before: 0.25 x 0.25 degrees when before they were only available at 0.4 x 0.4 degrees. In addition, based on user feedback, more parameters will be available in the coming days. These will enable limited-area modelling and machine-learning initialisation. Documentation can be found on the open data page for real-time forecasts.

“This change means open access to IFS medium-range forecast data at a much better resolution than before,” says ECMWF’s Deputy Director of the Forecasts and Services Department, Umberto Modigliani.

Medium-range data of the latest beta version of the AIFS are also made available at a resolution of 0.25 x 0.25 degrees. This is the resolution at which the AIFS is currently run. More information on the AIFS, including a link to access the data, is available on the AIFS machine learning data page.

“We're excited about the next step for the AIFS on the road to a full operational system, giving users data to test and use," says ECMWF’s Machine Learning Coordinator, Mat Chantry.

End of three-week delay for ECMWF’s contribution to S2S

A much-reduced delay is also applied to sub-seasonal to seasonal forecasts provided by ECMWF under a prediction project run by the World Weather Research Programme (WWRP) and the World Climate Research Programme (WCRP). ECMWF is one of many forecasting centres contributing to the project. Our forecasts are now released with only a 48-hour delay, rather than the previous three-week delay. The plan is to encourage all S2S data providers to agree to reduce the delay for their contribution. More information can be found on the S2S archive page.

“The reason this is important is that it will strongly increase the usefulness of the S2S database, making it possible to assess the value of the S2S forecasts near real-time,” says ECMWF scientist Frédéric Vitart.

End of six-day delay for CAMS weather forecasts

ECMWF provides daily global forecasts of atmospheric composition as part of its CAMS portfolio. These forecasts include all meteorological variables at 0.4 x 0.4 degrees. Data for pressure levels and some surface fields of these forecasts were previously only available after a six-day embargo. They are now available in real time, as they are for atmospheric composition products. More details on CAMS data can be found on the global atmospheric composition forecast data documentation page.

"Atmospheric composition and weather are inherently integrated, with interactions going in both directions. Having all meteorological fields available in the CAMS global forecasts supports a better and more comprehensive use of the data by many CAMS users," says the Deputy Director of CAMS, Richard Engelen.

“A significant upgrade”

Increasing amounts of open data at higher resolutions provide significant societal benefit: these datasets satisfy the World Meteorological Organization Unified Data Policy Core requirements, as well as making more data available for use in initiatives like Early Warnings for All (EW4All).

Altogether, this is a significant upgrade of ECMWF’s open data offering, which marks an important milestone in our move towards open data,” says ECMWF’s Data Policy & Partnership Coordinator, Emma Pidduck.