BARROWBLACK

Barrow Black Carbon Source and Impact Study

1 July 2012 - 30 June 2013

Lead Scientist: Rebecca Sheesley

Observatory: NSA

Long-range transport of black carbon (BC) is expected to have a large impact on Polar climate. Although atmospheric concentrations are low compared to populated regions in the northern hemisphere, deposits of the dark particles on snow and ice strongly influence the surface albedo and snow melt rates. Decreased albedo results in an increased melting of snow and ice, forming a positive feedback loop for warming in the Arctic. In order to understand and better quantify BC’s role in the climate forcing of the Arctic it is important to link source emissions with snow albedo impacts. In order to assess source contributions and impacts of BC on surface albedo in the Arctic, a combination of air monitoring, snow collection and the use of radiative measurements were conducted for the sample campaign at Barrow, with a follow-up of chemical analysis in the laboratories at Baylor University. For the air monitoring at Barrow, we set up two atmospheric particulate matter samplers and one optical BC instrument, in July 2012. The two atmospheric particulate matter samplers ran for 1 year and collected samples to be analyzed for carbon components. Additionally, we conducted radiocarbon analysis of the different carbon fractions. The results from the chemical and optical analysis of the collected particulate matter will be used in source apportionment modeling to determine the major source contributions for carbonaceous aerosol at Barrow. Intensive snow sampling was conducted prior to snowmelt during the spring of 2013. Snow was collected at a remote site, near the air monitoring station. The chemical analysis was conducted on the snow samples as well as the atmospheric samples, with a similar end point of source apportionment of the carbon components in the snow. The goal of the campaign was to characterize emission source contributions to atmospheric and snow-based black carbon, in order to establish links between emission source contributions and snow albedo impacts in the Arctic.