A model of thermospheric temperature and composition

An empirical model of thermospheric temperature (T_∞T₁₂₀, and s) and composition (H, He, N, O, N₂, O₂, and Ar) was derived from measurements of 8 satellites (AE-C, AE-E, AEROS-A, AEROS-B, ARIEL-3, ESRO-4, OGO-6, and SAN MARCO-3) and 4 incoherent scatter stations (Arecibo, Jicamarca, Millstone Hill, and St Santin). The altitude covered extends from 120 km up to about 600 km over the time period 1967 to 1976. The analytical framework used in the model resembles closely the MSIS setup: time independent terms, solar flux terms, geomagnetic activity (K_p) effect, annual (semiannual) and diurnal (semidiurnal, terdiurnal) variations, longitudinal terms, the U.T. effect, and corrections compensating for deviations from diffusive equilibrium at altitudes below 200 km. The model describes quiet to medium disturbed geomagnetic conditions (K_p ? 4) at solar fluxes (10.7cm) ranging from 60 to 180 × 10^?22 Wm^?2Hz^?1. To get an impression of the accuracy presently obtained, the model is compared with MSIS, Jacchia (1977), and the models of Thuillier (T_∞ and Engebretson (N). The best agreement is found for the temperature and the constituents He, O, and N₂ with increasing deviations in the order of H, N, Ar, and O₂.