1Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France
2Max-Planck-Institut für Meteorologie, Hamburg, Germany
3Columbia University, GISS, New York, USA
4University of Oslo, Department of Geosciences, Oslo, Norway
5Laboratoire d'Optique Atmosphérique, Université des Sciences et Technologies de Lille, CNRS, Villeneuve d'Ascq, France
6European Commision, Joint Research Centre, Institute for Environment and Sustainability, Climate Change Unit, Italy
7NCAR, Boulder, Colorado, USA
8Battelle, Pacific Northwest National Laboratory, Richland, USA
9NOAA, Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, USA
10ARQM Meteorological Service Canda, Toronto, Canada
11DLR-Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
12Institute for Marine and Atmospheric Research Utrecht (IMAU) Utrecht University, The Netherlands
13University of Michigan, Ann Arbor, MI, USA
14Universita degli Studi L'Aquila, Italy
15Kyushu University, Fukuoka, Japan
16NASA Goddard Space Flight Center, Greenbelt, MD, USA
17Goddard Earth Sciences and Technology Center, University of Maryland Baltimore County, Baltimore, Maryland, USA
18Hadley Centre, Met Office, Exeter, UK
19Service d'Aéronomie, CNRS/UPMC/IPSL, Paris, France
20Department of Environmental Science and Engineering, California Institute of Technology, Pasadena, USA
Abstract. The effects of unified aerosol sources on global aerosol fields simulated by different models are examined in this paper. We compare results from two AeroCom experiments, one with different (ExpA) and one with unified emissions, injection heights, and particle sizes at the source (ExpB). Surprisingly, harmonization of aerosol sources has only a small impact on the simulated inter-model diversity of the global aerosol burden, and consequently global optical properties, as the results are largely controlled by model-specific transport, removal, chemistry (leading to the formation of secondary aerosols) and parameterizations of aerosol microphysics (e.g., the split between deposition pathways) and to a lesser extent by the spatial and temporal distributions of the (precursor) emissions.
The burdens of black carbon and especially sea salt become more coherent in ExpB only, because the large ExpA diversities for these two species were caused by a few outliers. The experiment also showed that despite prescribing emission fluxes and size distributions, ambiguities in the implementation in individual models can lead to substantial differences.
These results indicate the need for a better understanding of aerosol life cycles at process level (including spatial dispersal and interaction with meteorological parameters) in order to obtain more reliable results from global aerosol simulations. This is particularly important as such model results are used to assess the consequences of specific air pollution abatement strategies.