A MODEL OF METEORIC IRON IN THE UPPER-ATMOSPHERE

A one-dimensional steady state model of meteoric iron in the Earth's u pper atmosphere has been developed. The model covers the altitude rang e 70 to 110 km at latitude 40 degrees N and allows for seasonal variat ions in the chemical composition, total density and temperature of the upper atmosphere. It addresses the three processes thought to be most influential in affecting the layer of free Fe atoms at approximately 85 km altitude, that is, the deposition of iron via meteor ablation, t he vertical distribution of the ablated material, and the partitioning of the metal among 10 constituent species as a result of neutral and ion gas phase reactions in dynamical steady state. A comparison betwee n calculated and observed average monthly Fe profiles reveals that man y features displayed by the meteoric iron layer (such as the peak heig ht and width, the small scale heights at the topside and underside, an d the seasonal changes in these parameters) can be successfully reprod uced by the model.