EAPS

Title:
 Causal Links Between the Arctic and the Midlatitude Jet-streams

Abstract:
The Arctic has been warming rapidly over the past few decades, raising the question of how polar warming may impact the weather in lower latitudes. Here, we apply causal discovery techniques (e.g. Granger causality) to quantify the sensitivity of the jet-streams to variations in Arctic temperatures on subseasonal timescales using 4800 years of CMIP5 model simulations. These causal discovery techniques allow us to quantify the jet-stream sensitivity in the presence of feedbacks, as well as assess seasonal and regional sensitivities. A further benefit of this approach is that we can make direct comparisons of the sensitivities between observations and models, as well as across many models, and here we demonstrate that model differences in the mean-state circulation can lead to differences in the jet-stream response to Arctic temperature variability.

While this talk is focused on the causal links between Arctic warming and the midlatitude atmospheric circulation, we hope it also highlights the relevance and utility of causal discovery techniques for atmospheric dynamics research.