Observing the vertical branch of the mesospheric circulation at latitude 60°N using ground-based measurements of CO and H2O

In this report daily ground-based measurements of vertical profiles of CO and H2O from 2002 are used to trace the vertical movement of air caused by the seasonally varying mean meridional circulation. In the spring (days 100–130) the estimated ascending velocity is found to vary with time and altitude from about between 250 m/day at 65 km altitude on day 100 to a maximum of ∼450 m/day at 85–90 km altitude on day 130. In the late summer and fall the descending velocity goes from 0 (when the downwelling starts) to ∼250 m/day at 75 km day 280. The mesospheric adiabatic temperature changes caused by the vertical movement of air are compared to mesopause temperature as estimated by the radiance of the Meinel band OH airglow.

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