HR: 09:30h
AN: SA21B-06 INVITED     [Abstracts]
TI: Physical and Chemical Properties of Meteoric Smoke
AU: * Plane, J M
EM: j.plane@uea.ac.uk
AF: University of East Anglia, School of Environmental Sciences, Norwich, NR4 7TJ United Kingdom
AU: Saunders, R E
EM: r.saunders@uea.ac.uk
AF: University of East Anglia, School of Environmental Sciences, Norwich, NR4 7TJ United Kingdom
AB: Somewhere between 10 and 100 tonnes (the current range of estimates) of interplanetary dust enters the earth's atmosphere each day. At least 60 percent of this ablates completely into atoms and ions, mostly between 70 and 110 km. This paper is concerned with the subsequent fate of the ablated metals and silicon. These species form a variety of oxides and hydroxides below 90 km, and it is widely believed that these species condense into nanometer-sized dust particles, known as "meteoric smoke". Here we will report laboratory experiments to simulate the production of meteoric smoke particles. Several chemical systems were investigated using a photochemical reactor: pure iron, iron-oxygen, silicon-oxygen and mixed iron-silicon-oxygen nano-particles. The particles were analysed for size distribution (diameter greater than 3 nm), chemical and physical structure and optical extinction. The kinetics of particle growth through condensation and coagulation were also measured in a novel aerosol flow tube. The results are used to refine aerosol growth models, and then to speculate on the likely form and size distribution of meteoric smoke in the mesosphere. Finally, we will consider how changes in the interplanetary dust flux could have affected the evolution of the earth's atmosphere.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0317 Chemical kinetic and photochemical properties
DE: 0325 Evolution of the atmosphere (1610, 8125)
DE: 0340 Middle atmosphere: composition and chemistry
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005