A time-resolved model of the Na layer in the mesosphere/lower thermosphere region is described. where the continuity equations for the major sodium species Na. Na+ and NaHCO3 are solved explicity. and the other short-lived species are treated in steady-state. https://www.spidertattooz.com/Kaiser-Copy-Stand-RS-1-with-RA-1-Arm-40-Counterbalanced-Column-and-18-x-20-Baseboard/