Modeling historical long-term trends of sulfate, ammonium, and elemental carbon over Europe: A comparison with ice core records in the Alps



[1] The regional EMEP chemical transport model has been run for the 1920–2003 period and the simulations compared to the long-term seasonally resolved trends of major inorganic aerosols (sulfate and ammonium) derived from ice cores extracted at Col du Dôme (CDD, 4250 m above sea level, French Alps). Source-receptor calculations have been performed in order to allocate the sources of air pollution arriving over the Alps. Spain, Italy, France, and Germany are found to be the main contributors at CDD in summer, accounting for 50% of sulfate and 75% of ammonium. In winter more European wide and trans-Atlantic contributions are found. The relative impact of these sources remains similar over the whole Alpine massif although transport from US and emissions from Spain contribute less as we move eastward from CDD, toward other alpine ice core drill sites like Colle Gnifetti (CG) in the Swiss Alps. For sulfate, the CDD ice core records and the simulated trends match very well. For ammonium, the trend simulated by the model and the summer ice core record are in reasonable agreement, both showing greater changes in ammonium concentrations than would be suggested by historical ammonia emissions. Motivated by a such good agreement between simulations of past atmospheric concentrations and ice core records for inorganic aerosol species, we also use the model to simulate trends in elemental carbon for which less information on past emission inventories are available.