The vertical connection of the quasi-biennial oscillation-modulated 11 year solar cycle signature in geopotential height and planetary waves during Northern Hemisphere early winter

The signals are strongest in the upper stratosphere. When the QBO is in its easterly phase (QBOe), it appears to move gradually eastward and poleward, resulting in a predominantly positive signal over the pole, with a weaker vertically connected negative signal over the Icelandic Low.

When the QBO is in its westerly phase (QBOw), the polar stratospheric signal is mainly negative and appears connected to a negative anomaly in the troposphere over the Aleutian Low. A spectral analysis of the stratospheric response in planetary waves showed a reduction of wave number 2 power under QBOe and an enhancement of wave number 3 under QBOw. These responses are characterized by an overall increase/decrease in wave activity at middle to high latitudes rather than a latitudinal shift of wave activity.