Lidar Discovery of AO and SAO of TINa Layers from the First Na Climatology of 75–150 km: Connections to Metallic Ions, Wave and Eddy Transport, and Meteoric Influx

First characterization of year-round thermosphere-ionosphere Na (TINa) layers (~105-150 km) is enabled with 7 years (2011–2017) of lidar observations over Boulder. Clear annual and semiannual oscillations (AO and SAO) are discovered in the nightly-mean TINa number density and volume mixing ratio (VMR) with the maximum in summer but minimum around spring equinox (Mar/Apr). The results are in stark contrast to the summer minimum and Nov maximum in the main Na layers (~75–105 km), supporting the theory of TINa formed via TINa+ ion neutralization. SAO in TINa VMR/density is linked to the thermospheric density SAO and the minimal wave/eddy transport around midlatitude equinoxes which hinders TINa+ ion production and upward transport via reduced diffusion of the main Na layer. Stronger TINa in autumn than in spring equinox is explained by the maximal and minimal meteoric input fluxes (MIF) occurring in Sep and Aprl, respectively.