Distribution of meteoric smoke – sensitivity to microphysical properties and atmospheric conditions L. Megner1, M. Rapp1,2, and J. Gumbel1 1Department of Meteorology, Stockholm University, Stockholm, Sweden 2Leibniz-Institute of Atmospheric Physics, Kühlungsborn, Germany
Abstract. Meteoroids entering the Earth's atmosphere experience strong deceleration
and ablate, whereupon the resulting material is
believed to re-condense to nanometre-size "smoke particles".
These particles are thought to be of great importance for
many middle atmosphere phenomena, such as
noctilucent clouds, polar mesospheric summer
echoes, metal layers, and heterogeneous chemistry.
The properties and distribution of meteoric smoke depend on poorly known or
highly variable factors such as the
amount, composition and velocity of incoming meteoric material,
the efficiency of coagulation, and the state and circulation of the
This work uses a one-dimensional microphysical model to investigate the
sensitivities of meteoric smoke properties to these poorly known or
highly variable factors. The resulting uncertainty or variability of meteoric smoke
quantities such as number density, mass density,
and size distribution are determined.
It is found that the two most important factors are the efficiency of the
coagulation and background vertical wind. The seasonal
variation of the vertical wind in the mesosphere implies
strong global and temporal variations in the meteoric smoke distribution.
This contrasts the simplistic picture of a homogeneous
global meteoric smoke layer,
which is currently assumed in many studies of middle atmospheric phenomena. In
particular, our results suggest a very low number of nanometre-sized smoke particles at the
summer mesopause where they are thought to serve as condensation nuclei for
Citation: Megner, L., Rapp, M., and Gumbel, J.: Distribution of meteoric smoke – sensitivity to microphysical properties and atmospheric conditions, Atmos. Chem. Phys., 6, 4415-4426, doi:10.5194/acp-6-4415-2006, 2006.