Biogenic Sources of Ice Nucleation Particles at the High Arctic Site Villum Research Station

The radiative balance in the Arctic region is sensitive to in-cloud processes, which principally depend on atmospheric aerosols, including ice nucleating particles (INP). High temperature INP (active at ≥-15°C) are common in the Arctic. While laboratory and limited in situ studies show that the high-temperature active INP are associated with bioaerosols and biogenic compounds, there is still little quantitative insights into the Arctic biogenic INP and bioaerosols. We measured concentrations of bioaerosols, bacteria and biogenic INP at the Villum Research Station (VRS, Station Nord) in a large number of snow (15) and air (51) samples. We found that INP active at high sub-zero temperatures were present both in spring and summer. Air INP concentration were higher in summer (18 INP m-3 at ≥-10°C) than in spring (<4 INP m-3 at ≥-10°C), when abundant INP were found in snowfall (1.4 INP mL-1 at ≥-10°C). Also, in summer, a significantly higher number of microbial and bacterial cells were present compared to the ...