Atmospheric black carbon in Svalbard

This is chapter 8 of the State of Environmental Science in Svalbard (SESS) report 2019 (https://sios-svalbard.org/SESS_Issue2). Black carbon particles are emitted into the atmosphere during combustion and reside in the air for days. Once emitted, they can be transported across thousands of kilometres and reach remote locations, like the Arctic. In the polar regions, black carbon has extremely important impacts on climate and environment. Because of its dark colour, it absorbs incoming solar radiation and can warm the atmosphere. Furthermore, black carbon that settles on the white surface of snow and ice favours their melting. Black carbon has been measured for decades in Svalbard, continuously at the high-altitude Zeppelin observatory, and during the warm seasons at the low-altitude Gruvebadet observatory, both near Ny-Ålesund village. Although the data show matching seasonal oscillations, the concentrations are generally higher at Gruvebadet, suggesting an impact of local emissions and demonstrating the complexity of vertical dynamics in the atmosphere. In 2018, unlike previous years, the two sites registered very similar concentrations. In Svalbard, the long-term records of black carbon measurements are complemented by short-term observations, performed during intensive experiments, cruises along the coasts, and vertical profile measurements. Such measurements reveal a large spatial variability of local black carbon sources and the impact of ship emissions. Vertical profiles clearly show the presence of black carbon layers at high altitude (above 1 km) during spring, likely due to long-range transport of pollution from lower latitudes during conditions of Arctic haze.