Atmospheric metal layers appear with surprising regularity

Science Daily  June 2, 2021
A team of researchers in the US (University of Colorado, UC Berkeley, Virginia Polytech, MIT) reported regular occurrence of mid-latitude thermosphere-ionosphere Na (TINa) layers over Boulder, Colorado. TINa layers occur regularly in various months and years, descending from ∼125 km after dusk and from ∼150 km before dawn. The downward-progression phase speeds are consistent with semidiurnal tidal phase speeds. One or more layers sometimes occur across local midnight. Elevated volume mixing ratios above the turning point of Na density slope suggest in situ production of the dawn/dusk layers via neutralization of converged Na+ layers. Vertical drift velocity of TINa+ aligned well with TINa, supporting this formation hypothesis…read more. Open Access TECHNICAL ARTICLE