Ten years of international collaboration on open source code

The Danish Meteorological Institute (DMI) and SMHI began working together on open source code for processing satellite data ten years ago. Today, this collaboration – Pytroll – involves more than one hundred experts and developers from around fifteen different countries, and the software has grown to become one of the most widely used platforms for real-time satellite data processing in Europe. Pytroll has enabled SMHI to process an ever larger volume of data for increasingly demanding external users.

A satellite view of Hurricane Ophelia in 2017
A satellite view of Hurricane Ophelia in 2017.

Ten years ago, SMHI’s satellite experts Adam Dybbroe and Martin Raspaud travelled by train to Copenhagen for discussions with three Danish colleagues at DMI on closer cooperation when developing software for operational satellite data processing. They used the same programming language (Python), and had the same type of data and the same needs. Both organisations found themselves in a situation where modernisation was essential but there was a lack of resources. Another goal was to avoid solutions that would result in maintenance and development being difficult and costly.

They began by meeting up every three months in Copenhagen or Norrköping, spending three or four days coding together. Interest in their work grew during 2011, with the Finnish and Icelandic weather services also coming on board.

“We held the first open workshop at SMHI in autumn 2012,” explains Adam Dybbroe. “In addition to SMHI and DMI, the workshop also included participants from the meteorological institutes in the Netherlands, Romania and Finland, and from EUMETSAT, the European Organisation for the Exploitation of Meteorological Satellites.”

Continued growth

Since then, Pytroll has continued to grow. Now, a number of Europe’s major meteorological institutions (including DWD in Germany and Météo-France) and EUMETSAT use and contribute towards the platform.

“The growing support and commitment we have received from EUMETSAT is particularly pleasing,” says Martin Raspaud. “Talented developers from across the Atlantic are now also involved, and Pytroll is now actively used in the USA and Canada.”

A high degree of activity

Pytroll’s global reach means that there is almost constant activity around the clock on pytroll.slack.com, where developers and users can hold discussions and help each other. The channel now has more than 300 members, with an average of around 60 active weekly users and approximately 200 messages each day.

Group with flag at Pytroll tenth year annicersary
Pytroll’s tenth anniversary celebrations brought together developers and users for a hackathon, Pytroll Contributor Week (PCW).

“For several years now, developers and researchers have been meeting twice a year and spending a week coding together,” concludes Adam Dybbroe. “At last week’s hackathon, which now goes by the name of Pytroll Contributor Week (PCW), we celebrated ten years with Pytroll. This involved continuing to improve and development the code so that we can deal with EUMETSAT’s new satellite programme, in which the first satellite is planned to be launched in around two years’ time.”

Pytroll stand at EUMETSAT user days November 2019
EUMETSAT held its user days in November, at which a Pytroll stand was presented. SMHI’s Adam Dybbroe attended the event.