Year-round Measurements and Results from Greenland Environmental Observatory at Summit (GEOSummit)

Long-term year-round sampling of the arctic atmosphere and surface snow provide insight to the relationship between aerosol and snow chemical compositions. Current research at the Greenland Environmental Observatory Summit Station (GEOSummit) includes high temporal resolution year-round IC and ICP-MS trace-element measurements of surface-snow and snow-pit samples, measurements of snow accumulation and spatial variability, DRUM aerosol size and S-XRF elemental atmospheric composition and other meteorological and snow properties. These measurements allow for a better understanding of the timing and magnitude of the seasonal cycle in elemental concentrations that are deposited and preserved in the snow pack. Elemental concentration records were analyzed using a multivariate factor analysis model called Positive Matrix Factorization (PMF) to identify unique source factors representative of sea salt, dusts and other potential sources such as biomass burning. The PMF source factors exhibit distinct seasonal cycles with significant year to year variability. Snow accumulation rates were concurrently measured, allowing evaluation of wet and dry deposition as well as quantification of the inter&ndashannual variability in seasonal snow accumulation. Source regions of specific events that transport dust or pollution from North America and/or Asia can be identified using the Lagrangian Particle Dispersion Model (LPDM) FLEXPART. Continuous longer-term records are fundamental to evaluate links between aerosol and snow chemistry to geophysical processes with multi-year periodicities (e.g. AO, NAO, etc.). Future plans include continuing research measurements at GEOSummit to better characterize elemental concentrations in snow and aerosols, annual to decadal variability in snowfall, and connections with atmospheric circulation and transport.