Biogenic volatile organic compounds and the fate of ozone in the changing Arctic

Most vegetation emit fragrant gases known as volatile organic compounds. Typically, the release of these gases increase with warmer weather. Temperature measurements have shown that the Arctic is warming faster than most of the planet from climate Change and it therefore it seems likely that the emissions of these compounds will increase more so than in other places. The investigators will study which compounds are emitted from arctic tundra vegetation and how the emissions of these compounds are dependent on weather, time of day, and season. The investigators will also explore how these compounds react in the atmosphere and what the products of these reactions are. A particular focus will be on the role that these gases play on boundary layer ozone, which is an important greenhouse gas and atmospheric oxidant. This research will be conducted at the Toolik Research Station, an ecological research site in northern Alaska. These studies will improve our understanding of how the natural environment in the Arctic interacts with the atmosphere. The broader impacts include graduate student education and support for a young faculty member at the University of Montana.

During previous Arctic work, these investigators have observed a clear diurnal signal in summertime boundary layer ozone. Attempts to relate this observation to the diurnal evolution of the atmospheric boundary layer have not been successful. These investigators propose that the daily emissions of biogenic volatile organic compounds (BVOC) from vegetation, and the subsequent chemical reactions in the atmospheric boundary layer, can explain this observation. A field campaign is proposed to quantify BVOC and NOx emissions at the Toolik Lake Long Term Ecological Research Station, located on the North Slope of Alaska. Continuous, 2-hourly ambient records of these BVOC will be obtained over two growing seasons. 3D-turbulence measurements and tethered balloon profiling will yield the first direct, continuous characterization of boundary layer mixing dynamics and mixing depth. Integration of observations into two hierarchic models will yield new insights into the fate of ozone in the Arctic atmosphere and its sensitivity to BVOC and NOx, and will provide advances in the understanding of atmospheric chemistry and oxidation in the Arctic atmosphere.