Atmospheric tide

Summary

Atmospheric tides are global-scale oscillations of the atmosphere whose periods are a solar or lunar day divided by a whole number. Unlike ocean tides, the largest atmospheric tides are forced by the daily cycle of solar heating, not by gravity. The lunar gravitational tide is much weaker. Classical tidal theory describes them as forced solutions of the Laplace tidal equations for the atmosphere. Their amplitude grows with height as the air density falls, and they dominate the winds of the upper mesosphere and lower thermosphere.