Tropospheric aerosol size distributions simulated by three online global aerosol models using the M7 microphysics module 1LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
2Max Planck Institute for Meteorology, Hamburg, Germany
3LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
4Pacific Northwest National Laboratory, Richland, WA, USA
Received: 21 January 2010 – Published in Atmos. Chem. Phys. Discuss.: 01 March 2010 Abstract. Tropospheric aerosol size distributions are simulated by three online global models
which employ exactly the same
aerosol microphysics module,
but differ in many aspects such as
model meteorology, natural aerosol emission, sulfur chemistry, and
The main purpose of this study is to identify
the influence of these differences on the aerosol simulation.
Number concentrations of different aerosol size ranges are compared among the
three models and against observations. Overall all three models are able to capture
the basic features of the observed spatial distribution.
The magnitude of number concentration is consistent
among the three models in all size ranges,
although quantitative differences are also clearly detectable.
For the soluble and insoluble coarse and accumulation modes,
inter-model discrepancies result primarily from
the different parameterization schemes for sea salt and dust emission,
and are also linked to the different strengths of the
convective transport in the meteorological models.
As for the nucleation mode and the soluble Aitken mode,
the spread of model results appear largest in the tropics and in the middle and
upper troposphere. Diagnostics and sensitivity experiments suggest that
this large spread is directly related to the sulfur cycle in the models,
which is strongly affected by the choice of sulfur chemistry scheme,
its coupling with the convective transport and wet deposition calculation, and
the related meteorological fields such as cloud cover, cloud water content, and precipitation.
Aerosol size distributions simulated by the three models are
compared against observations in the boundary layer. The characteristic shape and
magnitude of the distribution functions are reasonably reproduced
in typical conditions of clean, polluted and transition areas.
Revised: 15 June 2010 – Accepted: 06 July 2010 – Published: 14 July 2010
Citation: Zhang, K., Wan, H., Wang, B., Zhang, M., Feichter, J., and Liu, X.: Tropospheric aerosol size distributions simulated by three online global aerosol models using the M7 microphysics module, Atmos. Chem. Phys., 10, 6409-6434, doi:10.5194/acp-10-6409-2010, 2010.