Oxidant Production over Antarctic Land and its Export (OPALE) project: An overview of the 2010-2011 summer campaign

This paper summarizes the objectives and setting of the OPALE (Oxidant Production over Antarctic Land and its Export) project during summer 2010/2011 at Dumont d'Urville. The primary goal of the campaign is to characterize the oxidizing environment of the atmospheric boundary layer along the coast of East Antarctica. A summary of the relevant field chemical measurements is presented including the carbon monoxide and ammonia records that are used here to identify local influences due to station activities and penguin emissions. An overview of the basic meteorological conditions experienced by the site is presented including the results from the trajectory/dispersion model FLEXPART to highlight which types of air mass were sampled (marine boundary layer versus continental Antarctic air). The results of the FLEXPART analysis demonstrate that high ozone levels and related changes in the OH concentrations are associated with the transport of continental air to DDU. Finally, three companion papers are introduced. A first paper is dedicated to the impact of local penguin emissions on the atmospheric budget of several oxygenated volatile organic compounds. The second paper reports on HONO levels that were measured for the first time in Antarctica by using the long path absorption photometer (LOPAP) technique. Finally, in a third paper, major findings on the HOx levels are detailed, leading to the overall conclusion that the photochemistry at coastal East Antarctica is strongly driven by an efficient HOx chemistry compared to the situation at other coastal Antarctic regions.