Unpredictable weather, extreme rainfall or snow increasingly leads to challenges for people and nature. Paradoxically, less air pollution and cleaner clouds could lead to more extreme events. To understand how clouds will respond to changes in pollution, and in a post-fossil world is key for the world’s ability to plan for the future. This is at the heart of the EU-funded research project CleanCloud (Clouds and climate transitioning to post-fossil aerosol regime), comprised of 20 European research institutes with expertise in land- and space-based remote sensing, laboratory and in-situ atmospheric aerosol and cloud chamber experiments, and kilometer and large-scale aerosol, cloud, and climate modelling. CleanCloud, aims to quantify and understand regional and temporal effects of ACI-related processes, and how they will evolve in the transition to the post-fossil regime.

What is CHOPIN? - Springtime edition is a documentary film about the the 2024-2025 CleanCloud CHOPIN (Cleancloud Helmos OrograPhic sIte experimeNt) campaign at Mt.Helmos, Greece: where mythology, aerosols, clouds and climate meet. This movie showcases the efforts to establish observations that cover the whole mountain over multiple seasons and presents challenges, extreme conditions that the CHOPIN team had to overcome, but also the beauty and many fun moments experienced by the team. This is the Spring edition, which covers activities during the March-May 2025 period.

Mt. Helmos, in the heart of the Peloponnese, Greece rises to a height of 2,355 meters above sea level, is considered ideal for cloud and climate research. It sits at the crossroads of many different air masses, and in a “climate hotspot”, which like the Arctic, is changing much faster compared to the global average. This allows particles of almost any kind to interact with clouds, from wildfire smoke to pollution and highly processed particles from continental Europe, to sea salt from the Mediterranean and dust from Sahara, to pollen, bacteria, and fungal spores transported from thousands of kilometres away or the forest below. At the mountaintop station established by the NCSR Demokritos (called (HAC)2) researchers can directly observe inside clouds and "see” the interactions that are to be described in models. At the same time a whole array of remote sensing instruments is placed at the base of the mountain – cloud radars, lidars – at the installations of the Kalavryta Ski Center and used to remotely observe the clouds. A newly established measurement station, the HEMBA (operated by EPFL, NCSR Demokritos and FORTH) provide in-situ measurements that help constrain aerosol sources close to ground and differentiate from particles that come from far away. Altogether, the data will improve the understanding of aerosol-cloud interactions and serve as a testbed for evaluating existing and new remote sensing algorithms.

Don't forget to check out the other videos related to  CHOPIN on this channel!

Campaign PIs: Athanasios Nenes (FORTH/EPFL), Kostas Eleftheriadis (NCSR Demokritos), Alexandros Papayannis (EPFL/NTUA), Julia Schmale (EPFL), Alexis Berne (EPFL), Jean Sciare (CyI), Paul Zieger (SU), Stefano Decesari (CNR), Kalliopi Violaki (EPFL)

Media credits (in video). Interviews, video editing & montage: Nikitas Diamantopoulos

Acknowledgments: Funding was provided by the European Union’s Horizon Europe project “CleanCloud” (Grant agreement No. 101137639), the Swiss National Science Foundation projects "LipicAir" and “AAIDI”, the European Research Council (ERC) project "PyroTRACH" (Grant agreement No. 726165) and "INTEGRATE" (Grant agreement No. 865799) and the ATMO-Access project.

For more information, please contact the scientific PI of CHOPIN (Athanasios Nenes; athanasios.nenes@epfl.ch) or visit the CHOPIN website (http://go.epfl.ch/chopin-campaign) and the CleanCloud project website (https://projects.au.dk/cleancloud/cleancloud-project).