Investigating drivers of variability in model high-latitude trace gas distributions

Air pollutants in the Arctic have impacts on climate change, ecosystems, regional air quality, and human health. Rapid changes to and complex interactions within the Arctic environment due to climate change and socio-economic drivers mean that there is an urgent requirement to improve understanding of sources of Arctic air pollutants. Previous studies have identified significant deficiencies in model skill in simulating Arctic distributions of air pollutants, both at the surface and in the vertical profile. Such deficiencies in predictive capability and a lack of observations at high latitudes present major challenges to our ability to make credible near- and long-term projections of Arctic environmental change. Improved quantification of the relative contributions of different pollutant sources in the Arctic atmosphere, and their impacts is needed to provide a sound scientific basis for sustainable solutions and adaptive strategies. Here we investigate drivers of model variability in simulating tropospheric ozone and NOy in the high latitude troposphere. We use results from multi-model inter-comparison experiments compared with a limited ensemble of single model perturbation experiments to shed light on possible drivers of inter-model variability in Arctic ozone and NOy budgets. We also discuss implications for kinetic parameter uncertainties for confidence in modelled ozone in anthropogenic and biomass burning pollution plumes, and relevance to the Arctic. Our results serve as pointers to towards processes that could be targeted in future field or lab experimental efforts to reduce uncertainty in Arctic trace gas budgets.