This project will quantify the impacts of processes that control export of pollution from Europe on air quality, climate and ecosystems. These processes currently lack observational constraint, and our understanding is largely based on model simulations. We will conduct the first studies of European pollution export constrained by extensive aircraft and satellite observations, and quantify air quality and climate impacts. We will also quantify the role of ozone pollution from Europe in reducing CO2 uptake to European and Siberian forest, due to its harmful effects on vegetation. This will be compared with the direct climate impact of European ozone as a greenhouse gas. This will also allow quantification of a reduction in the effectiveness of CO2 emission cuts due to ozone limitation of carbon uptake to the biosphere, which is of urgent interest to policy makers and governments. Ozone is a pollutant in the lower atmosphere, which is not emitted directly, but is formed in the atmosphere by sunlight-driven chemical reactions acting on nitrogen oxides emitted from high-temperature fuel combustion (primarily motor vehicles, power plants, biomass burning) and volatile organic compounds, emitted from both man-made and natural sources. Ozone is a strong oxidant and a greenhouse gas in the lower atmosphere, and its concentrations have increased markedly since pre-industrial times. It is harmful to human health, and also damages vegetation. This leads to substantial reductions in crop yields, and also results in a reduction in the ability of vegetation to take up CO2 from the atmosphere - meaning it may result in further 'indirect' greenhouse warming. Export of pollution from the major continents in controlled by transfer of pollutants from the surface boundary layer (BL) to the overlying large-scale free troposphere (FT), where it can be transported over 1000s km. Over North America and Asia this 'venting' of the BL is controlled largely by fronts associated with low-pressure weather systems, however over central Europe these are much less frequent. Processes controlling European pollution export are much less well understood, and our lack of understanding is exacerbated by a lack of observations in regions downstream from Europe (mainly Arctic, Siberia and over the Mediterranean basin). Our approach will be to use new observations from aircraft experiments over the Arctic and Siberia, satellites and numerical models to quantify the roles of dynamic and chemical processes in controlling ozone pollution export from Europe. We will investigate how these processes determine the air quality and climate impacts of European ozone precursor emissions. In addition, we will determine how anthropogenic and natural processes interact to affect these processes, and quantify the impact of European ozone pollution on CO2 uptake to European and Siberian vegetation. We will finally quantify how these processes may change under future climate (year 2050).

Recent research has suggested that energetic particles entering the Earth's atmosphere at the poles can lead to 5-10 K changes in the surface tempertaures in polar regions during the wintertime. This is thought to be as a result of chemical changes driven by energetic particles enering the Earth's atmosphere at high altitudes (50-90 km) affecting the radiation balance of the atmosphere as a whole. However the exact nature of the particles is unknown, and further analysis/confirmation of the effect on surface temperature variability is limited by this knowledge gap. We propose to fill this knowledge gap by deploying low-powered narrow band radio receivers south of the Antarctic Peninsula in order to monitor energetic particle precipitation coming from the radiation belts that surround the Earth. Only then will the study of the impact of the particles in driving atmospheric chemical changes be possible with any degree of certainty. Being able to site our experiments in the Antarctic is critical because: 1) the geomagnetic latitudes of the sites chosen for this project are associated with processes occuring at the heart of the outer radiation belt - allowing us to determine the maximum radiation belt particle influence on the atmosphere; 2) the effect of energetic particle precipitation on the experimental radiowave observations that we will make is enhanced over thick ice-sheet regions - this condition only occurs south of the Antarctic Peninsula at the geomagentic latitudes that are needed to make the best observations; 3) the region south of the Antarctic Peninsula is where most of the particle precipitation from the outer radiation belt will occur, because of the influence of the nearby South Atlantic Magnetic Anomaly in knocking the energetic particles out of their orbits and into the atmosphere. The data collected, analysed and interpreted by the project partners brought together by this proposal, will allow us to model the chemical changes in the Antarctic atmosphere due to energetic particle precipitation. As a result we will be able to determine the impact of complex radiation belt processes on the global atmosphere. Our Investigation of the effects on polar surface temperatures is part of international efforts to understand climate variability and the links to the upper atmosphere (e.g. the NERC Science Themes, the Climate and Weather of the Sun-Earth System programme, phase II, and the International Living with a Star programme - ILWS) . Our proposal is also timely in that there will be extensive supporting measurements made during the lifetime of our proposal by x-ray balloons funded by NASA, and by new NASA and CSA radiation belt satellites, all supported by the ILWS programme. Extensive collaboration between this proposal and the balloon/satellite mission scientific teams has been initiated and will continue throughout the project lifetime.