Ice Nucleating Properties of Meteoritic Material

Abstract

A description is given of an attempt to duplicate the small particles formed by evaporation and recondensation during the flight of meteors in the atmosphere by heating meteors at a low pressure. A metallic meteorite produced entirely shiny spherules, almost all of which were in the size range 5 to 25 μ diameter, while a stony meteorite produced only irregular aggregates of tiny particles whose maximum dimensions were 0.1 to 0.2 μ. At water salutation and −10C, it is estimated that the iron meteorite creates about 10⁵−10⁶ ice nuclei per gram and the stony meteorite about 10⁸−10⁹. It is concluded that sufficient ice nuclei active at −15C are produced to explain observed concentrations in the troposphere.