1:45pm - 2:00pmTU3-2: 1
Particle size dependence of deposition ice nucleation at different temperatures
André Welti1, Patrik Luoma1,2, Ana A. Piedehierro1, Ari Laaksonen1,3
1Finnish Meteorological Institute; 2Aalto University; 3University of Eastern Finland
The effect of particle size on ice nucleation efficiency at different temperatures is investigated. Ice nucleation experiments were conducted using the SPIN chamber and size-selected dust particles. The measured size dependence is compared with predictions from classical and recent theories. Agreement in size dependence is used as an indicator of which theory best describes the observed ice nucleation mechanism. The results indicate that different ice nucleation mechanisms become active at different temperatures and on different dust types. The general observation of a disproportionately higher ice nucleation efficiency on larger particles should be considered when parameterizing ice nucleation in simulations.
2:00pm - 2:15pmTU3-2: 2
Terrestrial Sources Enhance Biogenic INP Levels in Coastal Waters and Atmosphere in Western Greenland
Christian Ditlev Funder Castenschiold1,2,3,5, Anne Ellebæk1, Kai Finster1,2,3,4, Thomas Bataillon5, Tina Šantl-Temkiv1,2,3,4
1Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark; 2Arctic Research Center, Department of Biology, Aarhus University, Aarhus, Denmark; 3iCLIMATE Aarhus University Interdisciplinary Centre for Climate Change, Aarhus University, Roskilde, Denmark; 4Department of Physics and Astronomy, Stellar Astrophysics Centre, Aarhus University, Aarhus, Denmark; 5Bioinformatics Research Centre, Aarhus University, Aarhus, Denmark
This study presents concentrations of Arctic marine and atmospheric ice-nucleating particles (INPs) at Disko Island, Greenland, from May to September 2023. We investigate the role of indigenous processes and the contribution of terrestrial runoff to biogenic INPs in coastal waters. The results revealed seasonal variations in INP concentrations, with biogenic marine INPs increasing during the summer and melt seasons. Further, we find terrestrial runoff as an important source of biogenic INPs in coastal waters. Atmospheric biogenic INP levels were predominately influenced by the extent of snow cover, underscoring the importance of local terrestrial sources in atmospheric INP concentrations.
2:15pm - 2:30pmTU3-2: 3
Terrestrial Runoff as a Source of Ice Nucleating Particles in Arctic Coastal Environments
Jennie Spicker Schmidt1,3,4, Nanna S. Rasmussen1, Lasse Z. Jensen1,3,4, Alina Mostovaya2, Johnna M. Holding2, Kai Finster1, Tina Santl-Temkiv1,3,4
1Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark.; 2Institute for Ecoscience, Marine Ecology, Aarhus University, Aarhus, Denmark.; 3Arctic Research Center, Aarhus University, Aarhus, 8000, Denmark; 4iCLIMATE Aarhus University Interdisciplinary Centre for Climate Change, Roskilde, 4000, Denmark
This study investigates the role of terrestrial runoff in supplying biogenic ice-nucleating particles (INPs) to the coastal marine environment of Young Sound fjord, Northeast Greenland, and their potential impact on Arctic cloud formation. Using flow cytometry, qPCR, and sequencing, we quantified microbial communities and INP concentrations in water and aerosols. Results show higher INP concentrations in the sea surface microlayer (SML) and river outlets compared to bulk seawater, with significant riverine input of warm-temperature INPs. We also found the SML plays a key role in aerosolizing biogenic INPs, highlighting the need for further investigation into marine contributions for climate models.
2:30pm - 2:45pmTU3-2: 4
Seasonal Dynamics of Bioaerosols and Ice Nucleating Particles in the High Arctic Atmosphere
Lasse Z. Jensen1,2,3, Andreas Massling2,3,4, Lise Lotte Sørensen2,3,4, Henrik Skov2,3,4, Frank Stratmann6, Heike Wex6, Kai Finster1,5, Tina Šantl-Temkiv1,2,3,5
1Department of Biology, Section for Microbiology, Aarhus University, Aarhus, 8000, Denmark; 2Arctic Reseach Center, Aarhus University, Aarhus, 8000, Denmark; 3iCLIMATE Aarhus University Interdisciplinary Centre for Climate Change, Roskilde, 4000, Denmark; 4Department of Environmental Science, Aarhus University, Roskilde, 4000, Denmark; 5Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Aarhus, 8000, Denmark; 6Institute for Tropospheric Research,Leipzig, 04318, Germany
The Arctic is warming rapidly, impacting cloud formation and precipitation. Bioaerosols, acting as high-temperature ice nucleating particles (INPs), play a crucial role, yet their representation in climate models remains uncertain. This study presents the first long-term dataset on bioaerosol composition and INP concentrations in the High Arctic (2021–2023). Preliminary results show seasonal shifts in microbial diversity and a strong correlation between airborne bacterial concentrations and warm-temperature INP levels. These findings highlight the need for integrating microbial ecology, aerosol chemistry, and meteorology to refine climate models and improve understanding of bioaerosol-driven cloud processes in the Arctic
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