Reflecting on the grand finale: highlights from our 4th km-scale Hackathon’s closing session

With a sunny morning in Hamburg (Germany), more than 130 participants attending the nextGEMS 4th km-scale Hackathon gathered at the Max Plack Institute for Meteorology (MPI-Met) on Friday, March 8th for the closing session. It started at 9:00 am, providing a space for the different thematic groups – Storms & Ocean, Storms & Land, Storms & Radiation, and Storms & Society – to share their observations, analysis, and first hacking results with everyone.

Postdoctoral Researcher at the MPI-M, Arjun Kumar, summarised outcomes from the Storms & Ocean breakout groups. For instance, it was found that the Arctic sea-ice holes in the ICON model – an issue that was at the center of attention during the last days -were caused by an error, whereby the ocean does not lose momentum to the sea ice. The role of ocean eddies and tropical cyclones on the carbon cycle were also explored in a novel one-year simulation with ocean biogeochemistry. Other topics included global vertical eddy heat fluxes; tropical precipitation biases; ocean mixing; the spatial scales of air-sea interactions; and declining fish stocks in the West African coast.

On behalf of the Storms & Land group, Postdoctoral Researcher at the University of Bern, Edgar Dolores Testillos, talked about the runs made with the IFS model. The team observed more frequent atmospheric blockings in different regions of the world, like the North Pacific. An atmospheric blocking indicates that the normal west-to-east flow of the air current in the upper levels of the Earth’s atmosphere (or jet stream) is disrupted or “blocked”. Consequently, they prolong the periods of certain weather conditions regionally, like heatwaves or heavy rainfalls, which makes blockings a crucial phenomenon to understand in climate modeling and weather forecasting due to its impact on ecosystems, agriculture, and society.

On another note, Thorsten Mauritsen, Researcher and Professor at University of Stockholm, shared the results from the Ocean & Radiation team, which was diversely integrated mostly by participants from outside the nextGEMS project. A highlight from the presentation were the haboobs (or sand storms) formations in the Sahara region, which were displayed in an astonishingly graphical way for the audience. Other aspects observed with the ICON model covered the low level of clouds in the Southern Ocean, and the distribution of areas where atmospheric conditions lead to the formation and release of precipitation – known as precipitation cells – that are reaching the Sahara region.

The  Storms & Society team, represented by Researcher at Barcelona Supercomputing Center, Eulália Baulenas, explained how during the hackathons knowledge is translated into action. Furthermore,  she shared the visual output that the group worked on to co-produce videos with Latest Thinking, as well as the preparation of a policy brief on km-scale modeling, which is currently in its beginning stage. Before finalizing, an important announcement was made by Project Coordinator, Heike Konow, about the future nextGEMS hackathon: it will happen in the city of Wageningen, in the Netherlands, from the 14th-18th of October 2024.

Lastly, as a final wrap-up, the hackathon community converged its knowledge in the final discussion panel, led by Bjorn Stevens, Managing Director of the MPI-Met. During this dialogue, the participants had the opportunity to address concerns about the Earth system models, the outputs, and the climate data, as well as ideas for future collaborative scientific publications and experiments.