Photo credit: Julia Burkart
It’s well known that the Arctic climate is influenced by anthropogenic contributions like heating during the winter and regional sources in the summer. But the chemistry of the aerosol environment and its influence on the cloud formation over the Arctic is less understood. Dr. Julia Burkart and Megan Willis, a postdoctoral fellow and Ph.D. student respectively, at the University of Toronto’s Department of Chemistry presented findings from their NETCARE summer aircraft campaign in Resolute Bay, Nunavut at the SOCAAR Seminar held on November 5.
The campaign focused on analyzing the interactions between oceanic aerosol sources with particles and clouds in the Arctic summertime. Measurements of trace gases, aerosol, and cloud properties were conducted from an aircraft flying over Resolute Bay, Nunavut.
The Arctic has a unique layered atmosphere in which a layer of warm air exists between an upper and lower cold air layer. This layer of warm air is known as the inversion layer because the air temperature increases with height, instead of the other way around. Currently, there is debate over whether new particle formation can or does occur in the Arctic air. The researchers presented their analysis which found high concentrations of ultrafine particles, in the 5-20nm range. They reported that 32% of the time the size distribution within the inversion layer is dominated by ultrafine particles.
The researchers also investigated the origin of these ultrafine particles and whether the particles can grow to cloud condensation nuclei sizes. The data collected from within the inversion layer showed low concentrations of carbon dioxide and little variation with altitude, indicating there was limited contributions of aerosols by transportation emissions. The growth of newly formed particles were observed in the inversion layer and also increasing concentrations of organic aerosols and methane sulfonic acid (MSA), indicating a marine biogenic influence on the particle growth. New particle formation was observed along with the growth of these small particles into the cloud condensation nuclei active size range. Additionally, low-level clouds were frequently observed and their properties were evaluated to be influenced particles originating from local sources.