The Arctic is experiencing a dramatic transformation as a result of anthropogenic climate change. The processes driving the accelerated change are not fully understood, yet they propagate through the entire global climate system with impacts on weather, ecosystems and geopolitics. Clouds play a major role in the Arctic system and are among the main contributors to the overall uncertainties of future predictions. How are clouds made and of what? To better understand cloud processes in clean atmospheric conditions, we chose to do measurements in the North Pole area where data are particularly scarce. Our experiment was set in a strategic time around the re-freezing period to investigate the change in the atmospheric particles as the season changes.

Within our project “Aerosol-cloud interaction in the high Arctic”, we installed various inlet systems to experimentally determine the microphysical and chemical properties of aerosols and cloud droplet residuals using a large suite of new experimental techniques. We determined the size, distribution and composition of particles with various instruments. These parameters are essential to understand cloud formation. For example, we found that particles around a few tens of nanometers are able to act as cloud condensation nuclei in the Arctic, which is relatively uncommon at our latitudes. An additional focus was the characterization of newly formed nano-particles. Gigabytes of data were recorded and the analysis will keep us busy for the next years.

Paul Zieger
Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University