On significant quantities of negative ions observed around the mesopause

Significant amounts of negative ions are sometimes observed at altitudes as high as the mesopause region (Kopp E. and Hermann L., 1984, Annales Geophysical2, 83; Ganguly S., 1984, J. atmos. terr. Phys. 46, 633). Using a suitable ion-chemical scheme in which water clustering to negative ions is also considered, the effect of change in temperature, T, and concentrations of NO, O, O₃ and H₂O on the abundance of negative ions in the mesopause region has been examined. It is shown that a drastic increase in the concentration of O₃ or a decrease in neutral temperature by about 20 K. around 85km could make the concentration of total negative ion comparable to that of electron.