Multi-year Measurements of Long-range Transport Impacts at Summit, Greenland

The long-range transport of anthropogenic and biomass burning emissions to the Arctic is known to have a significant impact on tropospheric composition, affecting levels of ozone precursors and ozone within both the Arctic and downwind regions. Long-term continuous measurements are essential to assess these impacts and improve current understanding on their magnitude and seasonal variability.

Here, we present year-round measurements of NO, NO2, PAN (peroxyacetyl nitrate), NOy (total reactive nitrogen oxides) and non-methane hydrocarbons (NMHC) along with observations of O3 taken at the GEOSummit site from summer 2008 to winter 2009. Results show that Summit is frequently impacted by transported anthropogenic and fire emissions from lower latitudes. These emissions are responsible for important shifts in nitrogen oxides and ozone. The analyses of these impacts along with FLEXPART transport simulations allow us to identify specific source regions. It is observed that the transport events during fall/winter were strongly dominated by emissions from North America and Europe. During summer, forest fire events can have a large impact on atmospheric concentrations observed at Summit. In particular, a large forest fire event in the Northwest Territories of Canada impacted Summit in early August 2008. During this event ozone is significantly correlated with PAN suggesting an enhancement in photochemically produced O3. Furthermore, elevated reactive nitrogen oxides levels were observed at Summit over a 2-week period indicating that additional photochemical O3 formation may occur during subsequent transport.