Abstract

I will talk about some recent work showing how the effect of the stratospheric polar vortex on tropospheric climate is modulated by El Nino/La Nina. I will also show that “continental winter warming” that is observed after strong volcanic eruptions is not a common feature of a strong polar vortex. The strongest tropospheric anomalies are found for warm ENSO and weak polar vortex. Finally I will briefly introduce a significant link of the Arctic Oscillation (which is linked to the polar vortex) with El Nino showing that without a positive AO index in spring there is no El Nino evolution even if the Seasonal Footprint Pattern (which is related to PDO ) is in favour of El Nino. This will allow me to introduce an “old” paper I have published in 1986 featuring Central Pacific warming as a prerequisite for El Nino.