WP4: SLCF and cryosphere

 

WP-leader: Radovan Krejci, email: radek (at) itm.su.se

Co-WP-leader: Andreas Stohl, email: ast (at) nilu.no

Co-WP-leader: Andreas Massling, email: anma (at) dmu.dk

 

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Aims

  • To characterize the spatial and temporal variability of Arctic short-lived pollutants (BC, OC, inorganic aerosol species, and ozone) and to investigate their trends
  • To quantify the importance of source regions and source types for the Arctic concentrations of anthropogenic aerosols and to determine their transport pathways
  • To calculate the direct radiative forcing of these SLCFs in the Arctic
  • To estimate the albedo effect of BC on snow and ice
  • To identify the role of bacteria and algae, carried by and deposited with aerosols, in snow

 WP4 will measure aerosol chemical composition, physical parameters and optical properties as well as ozone and other gase concentrations at the Arctic and sub-Arctic stations. Long-term measurements of CO, levoglucosan and other molecular tracers, combined with C-14 analysis clarify the origin of species (including BC) and the sources (agricultural fires, natural biomass burning, fossil fuel combustion, etc.) contributing to Arctic air pollution (comparison with WP7). To determine the aerosol vertical distribution and the associated radiative forcing, we measure ground-based and airborne measurements of aerosol optical depth.

 The data are used to validate chemical transport models and ESMs described in WP8, and also analyzed in combination with transport models and source-receptor models to determine the sources of SLCFs measured near the ground and aloft.

 Radiative transfer models are used to determine the impact of aerosols and ozone on the radiative forcing both at the surface and at the top of the atmosphere. With long-term measurements, changes in radiative forcing are determined.

 We measure the concentrations of BC in snow and the spectral albedo and grain size of snow in Scandinavia, Svalbard and Greenland, using a combination of ground-based measurements and remote sensing techniques with unmanned aerial vehicles. This allows studying the albedo impact of BC both directly and via enhanced ageing of the snow pack, and evaluating how well the ESMs can describe the snow albedo effect of BC.

 The number of microorganisms in filter-collected airborne particles and aerosols are determined. The filters are examined by electron microscopy to determine the number of microbial cells. Collected material is subjected to metagenomic analysis for the determination of the composition of the microbial community. and compared with snowpack to determine the contribution of airborne microbes to the colonization of snow cover. The data provides the foundation for studies on the microbial transformations of chemical substances and their effect on albedo.