Does the moon meddle with the lower ionosphere?

Abstract

At night free electrons of the lowest ionosphere are either lost by recombination with positive ions, or by attachment to neutrals thus forming negative ions. Whereas for ionisation photons of at least UV energy and/or energetic particles are required, visible light suffices to detach electrons from neutrals. One could compare mesurements of nights with and without moonlight, but one could never rule out that other factors such as temperature might also have changed between the two nights. Recent total lunar eclipses provide the opportunity to test the influence of moonlight assuming that the mesosphere does not change otherwise in the night under consideration. Results of several low frequency propagation paths are analysed, some of which indeed show ionospheric signatures of the transient disappearance of the moonlight.