Elemental carbon measurements in European Arctic snow packs

Abstract

Black carbon (BC) and other light-absorbing particles deposited on snow and ice are known to perturb the surface radiative balance. There are few published observations of the concentration of these particles in the snow in Scandinavia and the European Arctic. We measured BC concentrations in snow samples collected in this region from 2007 to 2009, and we present the results here. The data set includes 484 surface samples and 24 column samples (covering the accumulation season) from snow on land, glaciers, and sea ice. Concentrations up to 88 ng of carbon per gram of snow (ng/g) were found in Scandinavia, while lower values were observed at higher latitudes: 11–14 ng/g in Svalbard, 7–42 ng/g in the Fram Strait, and 9 ng/g in Barrow. Values compare well with other observations but are generally found to be a factor of 2–3 higher than modeled BC concentrations in snow in the chemical transport model Oslo CTM2. This model underestimation comes in spite of potentially significant undercatch in the observations. The spring melt period enhanced BC levels in surface snow at the four sites where the BC concentrations were monitored from March to May in 2008 and 2009. A data set of replicate samples is used to establish a concentration-dependent estimate of the meter-scale variability of BC concentration in snow, found to be around ±30% of the average concentration.