NOT SO GREEN | A Strange Thing - this QBO
Using radiosonde data from several equatorial locations around the world, the scientists discovered that the quasi-biennial oscillation began to deviate from its usual pattern in late 2015. At that time, westerly winds were descending in altitude and should have continued to sink and weaken as easterlies replaced them.
Instead, the westerly winds shifted upward and seemed to cut off the descent of high-altitude easterlies before they could begin their usual dominance. Additional easterly winds developed at lower altitudes in the stratosphere, beneath the rising westerlies. However, by June, the westerlies appeared to have resumed their normal descent.