Materials of the International Conference
50th Anniversary of the International Geophysical Year
and Electronic Geophysical Year

16-19 September 2007 • Suzdal, Russia

Linear model of nucleation burst in the atmosphere

A. A. Lushnikov1, M. Kulmala1, and Yu. S. Lyubovtseva2

1Department of Physical Sciences, University, Helsinki, Finland

2Geophysical Center, Russian Academy of Sciences, Moscow, Russia

Abstract

Now it becomes more and more evident that the nucleation bursts can contribute substantially to CCN production and can thus affect the climate and the weather conditions on our planet. Commonly accepted opinion connects the nucleation bursts with an additional production of nonvolatile substances in the atmosphere that can then nucleate and/or condense on newly born particles, foreign aerosols, or atmospheric ions. The production of nonvolatile substances, in turn, demands some special conditions to be fulfilled imposed on the emission rates of volatile organics from vegetation, current chemical content of the atmosphere, rates of stirring and exchange processes between lower and upper atmospheric layers, presence of foreign aerosols (submicron fraction, first of all) serving as the condensational sinks for trace gases and the coagulation sinks for the particles of nucleation mode, the interactions with air masses from contaminated or clean regions. Such a plethora of very diverse factors most of which have a stochastic nature prevents direct attacks of this effect. A theoretical modelling of the nucleation bursts is thus of primary importance. A simple linear (with respect to aerosol particle size distribution) model of nucleation bursts in the atmosphere is proposed. The model includes two sources of nonvolatile species, one of which nucleates producing the aerosol particles and the other one condenses onto the particles giving rise to their growth. The most important consequence of the linearity is that the particle size distribution can be presented as a superposition of different regimes. In particular, if the source-enhanced regime is combined with a free one, the latter produces a runaway mode in the particle size distribution appears. The model serves for estimating the CCN productivity by nucleation bursts.

Citation: A. A. Lushnikov, M. Kulmala, and Yu. S. Lyubovtseva (2007), Linear model of nucleation burst in the atmosphere, in: Materials of the International Conference '50th Anniversary of the International Geophysical Year and Electronic Geophysical Year', GC RAS, Moscow, doi:10.2205/2007-IGY50conf.

© 2007 Geophysical Center RAS and authors


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