Comment on esd-2022-50

Abstract

Warm temperature extremes can lead to devastating societal impacts, thus, the ability to understand and predict these events is vital to minimising their potential impact on society. We investigate the link between warm temperature extremes in Europe and anomalously persistent atmospheric circulation patterns for both winter and summer, along with some possible driving mechanisms. We assess atmospheric persistence leveraging concepts from dynamical systems theory, with this more mathematical approach being reconciled with the conventional meteorological view of persistence. We find that wintertime warm spells are typically associated with persistent zonal advection. Contrary to intuition, we find neither evidence of a link to anomalously persistent circulation patterns, nor a strong signal for warm temperature advection for summertime heatwaves. We thus argue that atmospheric persistence is not a necessary requirement for summertime heatwaves, and that local effects could play a much more important role than large-scale warm temperature advection for these events.