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? 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.

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.

Contents:
Act 1 (00:00-07:25) Inspiration & Launch. We talk about the inspiration behind the campaign, and outreach efforts to inspire young minds by participating in campaign activities, including radiosonde launches.

Act 2 (07:25-15:00) Metamorphosis, floating particles to clouds. We talk about the particle types that give cloud droplets and ice crystals, and the unique Helikite platform used during CHOPIN to understand the sources of particles and their variation with height up to where clouds start begin to form.

Act 3 (15:00-22:25) Echoes from air, particles and clouds. We present the use of cloud and laser remote sensing to study atmospheric motions, particles, and clouds to provide unique insights on the drivers of cloud formation and their modulators. CHOPIN data will be used to improve the ways remote sensing data is interpreted and develop new ways to look at the echoes obtained from the atmosphere. The low altitude station (HEMBA) is also toured around and instrments are explained, especially the one that measures CCN, which is so important for understanding aerosol-cloud interactions

Act 4 (22:25-30:33) From vision to reality. We talk about the vision and efforts of Dr.Kostas Eleftheriadis and his team at NCSR Demokritos to establish the (HAC)2 station that enabled the study of aerosols, clouds and greenhouse gases for monitoring, science and policy. Together with the combined vision, enthusiasm, efforts and devotion of all campaign partners, CHOPIN and its unique dataset became a reality.

Act 5 (30:33-37:08) Catching bugs and acid. We talk about the efforts to collect bioaerosols for studying their properties and ability to freeze water - and also the deployment of experimental sensing techniques to directly measure particle acidity - a critical but elusive property of particles - in the field. Apart from the sampling in the field, this Act also shows the "Enastron-Lab" (temporary laboratory setup in our hotel room) where samples are processed, preserved and the equipment is washed, disinfected and dried for next day's sampling.

Act 6 (37:08-42:18) One team, one dream. Mrs.Roula (owner of the hotel "Enastron" at Kalavryta where CHOPIN researchers stayed while in the field) provides her endearing and warm perspectives of the CHOPIN team and their efforts. The connection between the local community with the scientists and their strong support, commitment and hospitality provided throughout was a key for the success of CHOPIN. The stunning nature of Mt.Helmos, the beautiful village of Kalavryta with its relaxing atmosphere, rich history, activities and excellent food kept spirits high for the team - even during the most challenging phases of the experiment.

Act 7 (42:18-43:19) The full list of the CHOPIN team (ordered by institution)

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

Music during Act 4: Athanasios Nenes (FORTH/EPFL: piano).
F. Chopin (Nocturne in B-flat minor, Op. 9, No. 1, excerpt)
F. Chopin (Waltz in B minor, Op. 69, No. 2, excerpt)
F. Chopin (Fantaisie-Impromptu in C-sharp minor, Op. posth. 66, excerpt)

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).