Laboratory analogue of the QBO
jump to navigationThe Quasi-Biennial Oscillation (QBO) is a large-scale, roughly cyclic oscillation of the zonal (east-west) wind in the Earth's equatorial stratosphere, with an approximate period of around 2 years. It has been observed for more than 50 years now, and is widely understood to arise from the interaction between upward-propagating waves, generated in the troposphere, and the mean zonal flow at upper levels where the waves are dissipated. The basic mechanism was beautifully illustrated and verified in the laboratory in the late 1970s by Alan Plumb and Angus McEwan, working at CSIRO in Australia. Here we provide a brief introduction to the QBO in the Earth's stratosphere, and present an outline of Plumb & McEwan's original experiment together with some movies showing some of their remarkable results.