Quasi-Biennial Oscillation

The Quasi-Biennial Oscillation is a regular alternation of easterly and westerly wind bands in the equatorial stratosphere, each band forming near the top of the stratosphere and descending gradually over about a year until it dissipates near the tropopause, with a new band of the opposite direction already forming above it. Unlike most named atmospheric oscillations, its period is remarkably regular, averaging roughly 28 to 29 months, and it influences the strength and stability of the winter stratospheric polar vortex and, through it, tropical cyclone activity and mid-latitude winter weather. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/