CONTINUITY OF AIR MOTION IN MID-LATITUDE THERMOSPHERE

In the thermosphere vertical motions of air must occur in order to balance the divergence or convergence produced by the large-scale horizontal wind systems. The horizontal air velocities are found by solving the equation of motion of the neutral air, together with the equations of motion and continuity for the F-region ionization. The vertical air velocities that are then required to satisfy the neutral air continuity equation are of order 2 m sec-1 at mid-latitudes. The motion, which is additional to the vertical motion caused by thermal expansion and contraction, is generally upward by day and downward by night. The bearing of the results on the atmospheric circulation is briefly discussed. © 1969.