Definitions for "Quasi-biennial oscillation"
An oscillation in the zonal winds of the equatorial stratosphere having a period that fluctuates between about 24 and 30 months. This oscillation is a manifestation of a downward propagation of winds with alternating sign. This phenomenon is sometimes referred to as the stratospheric quasi-biennial oscillation to distinguish it from other atmospheric features that also have spectral peaks near two years.
A well-defined oscillation of the zonal wind component in the equatorial stratosphere, the 'period' being about 27 months. It is also termed 'stratospheric oscillation'. The range of the fluctuations, greatest at a level of about 25 km, decreases with distance from the equator. There is a phase lag from higher to lower levels. At a given level the phase does not appear to vary with longitude.
The name for the regular alternation of the mean zonal winds of the equatorial stratosphere between easterlies and westerlies which occurs every 24-30 months; that is, about every 2 years.