Wikipedia has the 'splainer for you[1]. There are good satellite examples online[2] But basically it has to do with buoyancy. A cloud or other layering of the

Wikipedia has the 'splainer for you[1]. There are good satellite examples online[2] But basically it has to do with buoyancy. A cloud or other layering of the atmosphere has a stable place in the vertical column. If the atmosphere passes over a mountain range that displaces the column vertically, the column returns to its normal position. In returning, the atmosphere overcorrects repeatedly and "bounces" back into position much like a single jump onto a mattress. [1] https://en.wikipedia.org/wiki/Gravity_wave https://en.wikipedia.org/wiki/Gravity_wave [2] https://twitter.com/ggweather/status/1427061411604099077 https://twitter.com/ggweather/status/1427061411604099077