Sources and seasonality of fluorescent aerosols in the Arctic

Aerosol‐cloud interactions play an important role in the Arctic climate but remain poorly understood. Ice nucleating particles (INPs) contribute to the formation of ice crystals at temperatures above ‐38 °C in mixed phase clouds, which are predominant in the Arctic. Therefore, investigating INP sources in the Arctic is crucial to understanding cloud occurrence, phase, and lifetime. One potential and very efficient source of INPs is primary biological aerosol particles (PBAPs). They can be long‐range transported or be emitted from local sources. PBAPs can be measured through their fluorescent properties. We present results of one year of fluorescent particle data, measured in the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) by a Wideband Integrated Bioaerosol Sensor (WIBS‐NEO). The observed, distinct seasonal cycle of fluorescent aerosol (FA) fraction and composition indicates different natural and anthropogenic sources throughout the year. We investigate how events, such as warm air mass intrusions, influence the FA population. Furthermore, we investigate co‐occurrences of FA and INP concentrations. This study provides valuable insights regarding the occurrence and sources of fluorescent particles in the high Arctic and their potential contributions to biogenic INP abundance