Ice nucleating particles in the marine boundary layer in the Canadian Arctic during summer 2014

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Irish, Victoria E., Hanna, Sarah J., Willis, Megan D., China, Swarup, Thomas, Jennie L., Wentzell, Jeremy J. B., Cirisan, Ana, Si, Meng, Leaitch, W. Richard, Murphy, Jennifer G., Abbatt, Jonathan P. D., Laskin, Alexander, Girard, Eric, Bertram, Allan K.
• Language: unknown
• Published: 2023
• Subjects: 54 ENVIRONMENTAL SCIENCES; Arctic; Hudson Bay; Baffin Bay; Canada; Hudson; Baffin
• Online Access: http://www.osti.gov/servlets/purl/1501757; https://www.osti.gov/biblio/1501757; https://doi.org/10.5194/acp-19-1027-2019

Ice nucleating particles (INPs) in the Arctic can influence climateand precipitation in the region; yet our understanding of the concentrations and sourcesof INPs in this region remain uncertain. In the following, we (1) measured concentrationsof INPs in the immersion mode in the Canadian Arctic marine boundary layer duringsummer 2014 on board the CCGS Amundsen , (2) determined ratios of surface areasof mineral dust aerosol to sea spray aerosol, and (3) investigated the source region ofthe INPs using particle dispersion modelling. Average concentrations of INPs at -15 , -20 , and -25 - C were 0.005, 0.044, and 0.154 L -1 ,respectively. These concentrations fall within the range of INP concentrations measuredin other marine environments. For the samples investigated the ratio of mineral dustsurface area to sea spray surface area ranged from 0.03 to 0.09. Based on these ratiosand the ice active surface site densities of mineral dust and sea spray aerosoldetermined in previous laboratory studies, our results suggest that mineral dust is amore important contributor to the INP population than sea spray aerosol for the samplesanalysed. Based on particle dispersion modelling, the highest concentrations of INPs wereoften associated with lower-latitude source regions such as the Hudson Bay area, easternGreenland, or north-western continental Canada. On the other hand, the lowestconcentrations were often associated with regions further north of the sampling sites andover Baffin Bay. A weak correlation was observed between INP concentrations and the timethe air mass spent over bare land, and a weak negative correlation was observed betweenINP concentrations and the time the air mass spent over ice and open water. Thesecombined results suggest that mineral dust from local sources is an important contributorto the INP population in the Canadian Arctic marine boundary layer during summer 2014.