Towards free and open weather data for all

The European Centre for Medium-Range Weather Forecasts (ECMWF) is moving towards open data, writes Umberto Modigliani.
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By Umberto Modigliani

Umberto Modigliani is ECMWF’s Deputy Director of Forecasts, responsible, with the Department Director, for the 24/7 production of forecasts and for liaison with users.

28 Sep 2020

Early October will see the European Centre for Medium-Range Weather Forecasts (ECMWF) take a major step towards making hundreds of its forecast maps free and available to all. The changes are part of wider moves across Europe to make public sector data free and open, to encourage innovation and to support a thriving, data-based digital economy.

Charts will cover the whole world, all types of weather situations including extreme events, and, very importantly, will also include probability-based information, providing guidance on forecast confidence.

Up till now, full access to these forecast charts was restricted to the national meteorological and hydrological services of ECMWF’s Member and Co-operating States, World Meteorological Organisation members and commercial customers. Access was subject to a range of bespoke licences and often incurred charges.

Forecasts of precipitation and mean sea level pressure are just one example of the hundreds of ECMWF charts that will be made available.

Forecast charts will be free and open, so users can share, redistribute and adapt the information as they require, even for commercial applications, as long as they acknowledge ECMWF as the source.

Andy Morse, Professor of Climate Impacts at the University of Liverpool, commented: "The potential uses and benefits these products bring for a range of users and sectors is vast and particularly key in less economically developed countries. Now that remote internet access is widespread through modern mobile phone networks; the availability of this information is likely to be a game changer for many small enterprises. In my experience, people in these most remote parts of the world are hungry for such information."

The changes also mean a move to an open data policy for historical information in ECMWF’s huge repository, which contains billions of meteorological fields including recent and past forecasts. It represents the largest archive of such data in the world.

“The societal benefits associated with free and open data are big. We are aware that the move comes with its financial challenges, but the benefits outweigh those challenges” Rolf Brennerfelt, Chair of ECMWF Policy Advisory Committee

Under the EU Open Data Directive, EU Member States will be required to make as much information available for re-use as possible. Weather forecasts are considered as ‘high value’ data, the re-use of which is associated with particularly important benefits for society and the economy.

The EU Copernicus Earth observation programme, several elements of which are implemented by ECMWF, has operated a policy of free, open data since its inception. With many thousands of users, the programme offers a host of examples of the benefits that open data can bring.

At the start of the COVID-19 pandemic, a group of Italian epidemiologists used atmospheric pollution data from the EU Copernicus Atmospheric Monitoring Service (CAMS) to investigate links between the level of pollution in a given area, and the rate and seriousness of COVID infection. The Copernicus Climate Change Service (C3S) has developed an application that allows health authorities and epidemiology centres to explore whether temperature and humidity affect the spread of the coronavirus.

With hundreds of petabytes of data, ECMWF’s vast repository is the epitome of the term ‘big data’. It offers immense opportunities for machine learning, where a computer uses data to ‘learn’ relationships between different variables. If there are sufficient data for training, machine learning can be used to develop numerical tools that can mimic complex systems. In fact, researchers are coupling these ECMWF data and machine learning to investigate the development of a ‘digital twin’ of the Earth system. Wider applications such as anticipating weather effects on financial markets can also be envisaged.

Rolf Brennerfelt, Chair of ECMWF Policy Advisory Committee, commented: “ECMWF Member States have been keen for the Centre’s data to be open and free for a while.

The societal benefits associated with free and open data are big. We are aware that the move comes with its financial challenges, but the benefits outweigh those challenges.

We are in a period of transition, and this first batch of data being made freely available is a very good start and illustrates well our commitment to this principle.”

This phased move towards free and open data aims to support creativity and innovation in the field of scientific research as well as weather applications, and should enable more necessary and critical scientific, social and economic advances.

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