Resolving the strange behavior of extraterrestrial potassium in the upper atmosphere

Abstract

It has been known since the 1960s that the layers of Na and K atoms, which occur between 80 and 105 km in the Earth's atmosphere as a result of meteoric ablation, exhibit completely different seasonal behavior. In the extratropics Na varies annually, with a pronounced wintertime maximum and summertime minimum. However, K varies semiannually with a small summertime maximum and minima at the equinoxes. This contrasting behavior has never been satisfactorily explained. Here we use a combination of electronic structure and chemical kinetic rate theory to determine two key differences in the chemistries of K and Na. First, the neutralization of K+ ions is only favored at low temperatures during summer. Second, cycling between K and its major neutral reservoir KHCO3 is essentially temperature independent. A whole atmosphere model incorporating this new chemistry, together with a meteor input function, now correctly predicts the seasonal behavior of the K layer.

Description
Keywords
potassium layer, mesospheric metal, meteoric ablation
Citation
Plane, J. M. C., Feng, W., Dawkins, E., Chipperfield, M. P., Höffner, J., Janches, D., & Marsh, D. R. (2014). Resolving the strange behavior of extraterrestrial potassium in the upper atmosphere. 41(13). https://doi.org//10.1002/2014GL060334
License
CC BY 3.0 Unported