Research in polar regions has demonstrated that chemical and physical interactions between the snowpack and the atmosphere have a substantial impact on the atmosphere's composition. Deposition and scavenging of gases and aerosols result in the accumulation of a chemical reservoir that, under conditions of increasing temperature and solar irradiance, can turn into a photochemically active reactor. These reactions form radicals and the release of chemicals into the atmospheric surface layer, and consequently influence concentrations and budgets of important tropospheric trace gases. 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 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. 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 and a coastal area during a wide variety of environmental and seasonal conditions.
Intellectual Merit: This project will measure diurnal and seasonal ozone fluxes and deposition rates over polar snowpack. Ozone surface fluxes will be analyzed for their relation to environmental and snow photochemical processes. Data will be incorporated into atmospheric three dimensional chemistry and transport models. Estimates of the overall ozone sink of polar regions and the impact of predicted environmental changes on the tropospheric ozone budget will be developed.
Broader Impacts: This research will establish a new collaboration between two early career scientists in the fields of atmospheric analytical instrumentation development and field research and data assimilation and integration into atmospheric models. Ozone flux measurement techniques will be thoroughly tested and characterized for use in the Arctic environment and in future research. A female graduate student will be supported for her Ph.D. Undergraduate students, in particular minority and underrepresented groups, will participate through internships and summer study projects. Data will be made available at the ARCSS Data Coordination Center archive at the National Snow and Ice Data Center. This research will contribute to improving our understanding and predictive capabilities of future changes of tropospheric ozone and role in anthropogenic radiative greenhouse gas forcing. Consequently, this research will contribute towards improving global change predictions and in directing society responses.
