Sources and abundance of ice nucleating particles derived from long-term measurements at high time resolution

Ice Nucleating Particles (INPs), a minor and strongly temperature dependent fraction of atmospheric aerosol particles, are key players in the weather and climate systems be inducing the formation of ice in mixed-phase and cirrus clouds. There is increasing evidence that INPs not only induce the formation of precipitation in particular over continental areas, but also have an important impact on a number of radiatively important clouds types throughout the troposphere. New insight into the abundance, types, and sources of INPs, and by that also into their various roles in the atmosphere, can be obtained by longer-term measurements at high time resolution. Such measurements can be conducted with the PINE (Port-able Ice Nucleation Experiment) instrument, which was developed for both, flexible operation during dedicated laboratory experiments on ice nucleation processes and for automated operation during longer-term INP monitoring activities in the field. This contribution will give a short introduction into the topics of primary ice formation and ice-nucleating particles, and will present and discuss examples of recent longer-term records of INP measurements with the PINE instrument at different European field sites like the Sonnblick Observatory in Austria, the Helmos observatory in Greece, the Zeppelin observatory in Spitzbergen, or the National Atmospheric Observatory Kosetice in the Czech Republic. These locations will also become observatories as part of the pan-European infrastructure ACTRIS for longer-term monitoring of aerosols and INPs.