Relative intensities of middle atmosphere waves

At extratropical latitudes, gravity waves mostly play a major role. Traveling planetary waves are found to play a secondary role. Quasi-stationary planetary waves and tides yield a lesser contribution there.

Vertical profiles of total temperature fluctuations show a sharp vertical gradient change ("kink" or "bend") in the mesosphere. This is interpreted in terms of a change of wave damping, and the concept of a "wave turbopause" is suggested. The altitude of this wave turbopause is found to be mostly determined by the relative intensities of gravity waves and planetary waves.

The turbopause is further analyzed, including earlier mass spectrometer data. It is found that the wave turbopause and the mass spectrometer turbopause occur rather close together. The turbopause forms a layer about 8 km thick, and the data suggest an additional 3 km mixing layer on top.