Comment on 'Ice iron/sodium film as cause for high Comment on 'Ice iron/sodium film as cause for high

摘要

P. M. Bellan has recently published a paper [Bellan, 2008] (hereafter B08) in which he claims that electrons in a metallic layer formed on the surface of mesospheric ice particles are the main source for strong radar echoes, which were first detected by Czechowsky et al. [1979]. These echoes are commonly called PMSE (polar mesosphere summer echoes). We argue that instead electrons in the gas phase are causing PMSE. The difference is potentially important for the interpretation of PMSE and related background atmosphere conditions. There are basically two main arguments against the metal electron theory of B08: (1) there is a wealth of experimental proof that free electrons cause PMSE (and not electrons in a metal layer), and (2) it is extremely unlikely that a metallic layer can form on the surface of ice particles. In our comment we expatiate on these arguments in more detail.