STRUCTURE OF THE UPPER ATMOSPHERE.

General information on the structure, composition, temperature, and motion of the upper atmosphere is reviewed. The factors governing the form and intensity of the atmospheric circulation are established. Note is taken of the importance of vertical transport, which determines the distribution and variations of ozone in the stratosphere on the one hand and the composition and ionization of the D-layer of the ionosphere on the other. The dominant role of the diurnal radiation cycle in transformation of all thermospheric phenomena is established. The effects of magnetohydrodynamic forces in various layers of the upper atmosphere are given, and it is shown that their contribution weakens in the lower ionosphere at night, while the motion in the upper atmosphere depends at all hours chiefly on magnetic friction and the Coriolus force. These conclusions are confirmed by available experimental data.