The leading idea of this project is to make a breakthrough in understanding the sources and distribution of the few ice forming particles in the atmosphere that generate mixed-phase and ice clouds. Ice containing clouds shield the surface from solar radiation and produce rain and snow fall. The nature and sources of ice forming particles that affect the clouds in Finland are unknown. They could be inorganic particles, like desert dust transported over long distances in the high atmosphere or biological particles like bacteria, spores and pollen from the local boreal forest. The objectives of this project are: • Identifying the sources and quantifying the abundance of ice forming particles across Finland • Understand the contribution of biological sources throughout the year This information is highly valuable input for climate and weather models and for our understanding of ice formation by particles in the atmosphere.

2021

2025