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.

The Arctic is warming up to 4 times the global average, leading to rapid ice melting and a drastic change of the sources of aerosols and their impact on clouds. Natural aerosols are also a major driver of these changes. Monitoring of these changes is extremely sparse, especially in the most remote regions where harsh conditions make it difficult to carry out even simple measurements over time. Because of this, models of climate change for this remote region are virtually unconstrained by observations, making predictions highly uncertain. CleanCloud addresses important knowledge gaps, both by providing observations of Arctic aerosols and their interactions with clouds, and by testing algorithms used for remote sensing of aerosols and clouds by satellites and developing new ones.

Here we present a short video documentary with scenes and pictures from the 2024 CLeancloud Arctic VIllum ExpeRiment (CLAVIER) - Sumer Phase campaign at Villum, Greenland, showcasing the challenges, extreme conditions that the CleanCloud team had to overcome, but also the beauty and rapidly changing conditions in the Arctic. Also see Dr.Romanos Foskinis (LTE/LAPI@EPFL) setting up the NTUA ARIS lidar that was deployed throughout the campaign, and a rendez-vous with NASA ArcSix aircraft. Villum research station is located in one of the most remote and extreme environments on Earth, which makes it an exceptional site for studying the Arctic climate, atmosphere, and ecosystem.

Campaign PIs: Henrik Skov (Aarhus U), Andreas Massling (Aarhus U), Athanasios Nenes (FORTH/EPFL), Alexandros Papayannis (NTUA/EPFL), Holger Siebert (TROPOS), Michael Schäfer (U.Leipzig)

Media credits:

• Video: Romanos Foskinis (EPFL)
• Music: Athanasios Nenes (FORTH/EPFL: solo piano)
  M.Newmann Terpsichore (variation); Alex Dunn (clarinet); D.Giammar (cello), M.Han (violin)
  L.v.Beethoven (Piano concerto no.3 in C minor, op.37: excerpt & cadenza from I:Allegro con brio); Vasilis Katsaros (orchestral piano).

Acknowledgments:
Funding was provided by the European Union’s Horizon Europe project “CleanCloud” (Grant agreement No. 101137639) and the European Research Council (ERC) project "PyroTRACH" (Grant agreement No. 726165).

For more information, please contact the CleanCloud coordinators Ulas Im (ulas@envs.au.dk) or Athanasios Nenes (athanasios.nenes@epfl.ch).