HR: 10:50h
AN: SA22A-03    [Abstracts]
TI: Charged Meteoric Smoke Particles: In-situ Observations And Their Interpretation by Charging Models
AU: Rapp, M
EM: rapp@iap-kborn.de
AF: Department of Meteorology, Stockholm University, Svante Arrhenius vaeg 12, Stockholm, 10691 Sweden
AU: Rapp, M
EM: rapp@iap-kborn.de
AF: Leibniz Institute of Atmospheric Physics, Schlossstr. 6, Kuehlungsborn, 18225 Germany
AU: * Gumbel, J
EM: gumbel@misu.su.se
AF: Department of Meteorology, Stockholm University, Svante Arrhenius vaeg 12, Stockholm, 10691 Sweden
AB: Meteoric smoke particles have been suggested to play a major role in a wealth of atmospheric processes like noctilucent clouds, polar mesosphere summer echoes, metal atom layers, and mesospheric chemistry. A convenient way to observe these particles has been to take advantage of the fact that the particles are expected to be charged (by processes like electron and ion capture and photoemission) and can hence be observed with in situ experiments suitable for the detection of heavy charge carriers. However, in order to interpret such measurements of charged species for example in terms of the total number density of all particles (i.e., whether charged or not), a detailed and quantitative understanding of the relevant charging processes is imperative. In the current paper, we address the problem of the charge of meteoric smoke particles in the presence of free electrons, and negative and positive ions. In particular, we compare the results from discrete and continuous charging models and we show that in the particle size and temperature range of relevance here (i.e., radii < 10nm, T ~ 200 K) the different model approaches disagree considerably. In order to clarify which of these model results is physically reasonable and also to study the time dependence of the charging process we have developed a new particle charging Monte Carlo model that allows to study the charging of a smoke particle ensemble for a wide range of possible atmospheric parameters. Finally, our findings are applied to the interpretation of recent in situ measurements of charged meteoric smoke particles in the course of the European ECOMA-project (ECOMA = Existence and Charge state Of meteoric smoke particles in the Middle Atmosphere).
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0340 Middle atmosphere: composition and chemistry
DE: 2461 Plasma interactions with dust and aerosols (7849)
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005