Can tropospheric configurations linked to the onset or aftermath of polar vortex decelerations be distinguished from climatology?

Wintertime stratospheric circulation in the Northern Hemisphere is dominated by a strong and persistent westerly polar vortex. However, every one to two years, this system undergoes a strong disruption associated with a fast deceleration or even a reversal, accompanied by a massive warming of the polar stratosphere. The tropospheric impacts of these extreme events, commonly referred to as “sudden stratospheric warmings” (SSWs) are well documented, but their precursors and subsequent responses in the troposphere remain frustratingly difficult to categorize systematically. Using recent advances in dynamical systems theory applied to the atmosphere, we analyze from a general point of view, the relationship between very anomalous stratospheric states and tropospheric configurations. We find that highly anomalous geopotential configurations at 10 hPa are unequivocally associated with the occurrence of a strong stratospheric vortex deceleration. However, no distinctive tropospheric patterns can be identified either prior to or following these events. This suggests that both tropospheric precursors and responses to extreme vortex decelerations are fundamentally nonspecific and in consequence, they could be statistically indistinguishable from the background tropospheric variability.