Radiosondes data showing the Quasi-biennal oscillation of the stratospheric wind direction near the Equator.
<a href="https://en.wikipedia.org/wiki/User:Morn" class="extiw" title="en:User:Morn">Morn</a>. Graph made using data from <a rel="nofollow" class="external text" href="http://www.jisao.washington.edu/data_sets/qbo/">FU Berlin</a>
English Wikipedia