Evidence for New Particle Formation in the Summertime Arctic near Resolute Bay, Nunavut, Canada

Airborne measurements of the atmospheric aerosol were conducted from Resolute Bay, Nunavut (Canada) during July 3-23, 2014 as part of the Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments (NETCARE). The measurements were taken from the Alfred Wegener Institute (Germany) POLAR 6 DC-3 aircraft on 11 research flights and 8 ferry flights (Toronto to Resolute Bay return). The aircraft was deployed with several aerosol instruments, gas monitors and basic meteorological instruments. Particle size distributions were characterized using a BMI SMS, a DMT UHSAS and a GRIMM OPC. Total particle number concentrations were measured using a TSI CPC 3787 and cloud condensation nuclei concentrations were measured with a DMT CCN Counter. Aerosol chemical components were measured with a DMT SP2, an Aerodyne SP-AMS and the Mainz single particle mass spectrometer, ALABAMA. Low level flights were conducted over ice, water and melt ponds etc.), and vertical profile data were regularly collected up to 3 km over areas of Lancaster Sound and the Wellington Channel. We focus on frequently observed high concentrations of small particles (<20nm) which are likely an indication for new particle formation (NPF). During such NPF events concentrations of small particles increased from a few tens up to a few thousand per cubic centimeter. The majority of these events were observed approximately 60 m above the water or ice surface with a few observed at higher altitudes between 2 km and 3km. Most of the NPF events were characterized by low pre-existing particle surface areas or low condensation sinks. In general, the cases of NPF were associated with very few particles >100nm), and most of the particles were smaller than 20nm. In at least two cases, the concentrations of particles between 20 nm and 50 nm were observed to increase, indicating some growth of the newly formed particles. The NPF events will be associated with meteorological influences as well as the underlying surface: solid ice, open water, melt ponds. The CCN measurements, made at a supersaturation of 0.8%, will provide information on hygroscopicity of particles that have grown to between 30 nm and 50 nm. In a final step, the data will be linked to particle and gas composition measurements, including MSA (methane sulfonic acid) and DMS (dimethylsulfide).