Surface-Atmosphere Ozone Fluxes at Summit, Greenland

Previous research in Polar Regions has demonstrated that chemical and physical interactions between the snowpack and the overlaying atmosphere have a substantial impact on the composition of the atmosphere. Deposition and scavenging of gases and aerosols result in the accumulation ofa chemical reservoir that subsequently, under conditions of increasing temperature and solar irradiance can turn into a photochemically active reactor. These reactions result in the formation of radicals, the release of chemicals into the atmospheric surface layer, and consequently influence concentrations and budgets of important tropospheric trace gases. Recent observations of photochemical depletion of ozone in firn air, diurnal ozone trends in the surface layer, tethered balloon vertical profile data and estimates of photochemical ozone production all imply that ozone deposition to the snowpack depends on parameters including the quantity and composition of deposited trace gases, solar irradiance and snow temperature. Consequently, ozone surface fluxes in Polar Regions are expected to have snow photochemical, diurnal and seasonal dependencies and to overall be more complex and possibly larger than considerations in global atmospheric models. Current literature does not reflect these conditions and ozone flux estimates to year-round snow are contradictory and are suspected to have large errors. The objective of this research is to study the diurnal and seasonal ozone deposition to the year-round snowpack and investigate dependencies of ozone deposition on environmental and snow photochemical conditions. This study will employ sensitive flux measurement approaches by eddy correlation, by the tower gradient method and by measurements of ozone in the interstitial air. Field measurements will be performed during three experiments at Summit, Greenland during a wide variety of environmental and seasonal conditions.