ARCAEROMIX

Significant delays in fall sea ice freeze-up in the Chukchi and Beaufort Seas are reducing winter sea ice extent and resulting in thinning sea ice prone to fracturing. The open water in the Alaskan Arctic results in wintertime sea spray aerosol emissions. However, the majority of recent Arctic aerosol observations have been made through intensive spring/summer field campaigns, with few measurements in the fall-winter. This observational gap is limiting our understanding of the spatial and temporal variability in the Arctic aerosol population, as recognized by current international efforts focused on improving understanding and prediction of the Polar Regions (e.g., Year of Polar Prediction, International Global Atmospheric Chemistry Project activity CATCH (Cryosphere and Atmospheric Chemistry)). The Aerosols during the Polar Utqiaġvik Night (APUN – ‘snow on ground’ in Iñupiaq) ARM field campaign on the North Slope of Alaska (NSA) will improve our understanding of atmospheric aerosol sources, composition, and processes during the early Polar Night (Nov. – Dec.) when sea ice freeze-up is expected to occur near Utqiaġvik (formerly known as Barrow), Alaska. We will deploy an aerosol time-of-flight mass spectrometer (ATOFMS) for measurements of individual particle size and chemical composition in real time. In addition, online aerosol size distribution measurements will be conducted, and particles will be collected for offline analysis via electron microscopy with energy dispersive X-ray analysis. These detailed aerosol measurements will be complemented by routine aerosol and meteorological measurements made at the ARM NSA Facility and NOAA Barrow Observatory. This field campaign addresses the key ASR research areas of ‘Aerosol Processes’ and ‘High-Latitude Processes’. This results of this ARM field campaign will be compared to aerosol composition measurements during the MOSAiC ARM field campaign, as part of PI Pratt’s DOE Early Career award.

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