Extremely Warm European Summers Driven by Sub-Decadal North Atlantic Heat Inertia
Abstract
Previously found mechanisms on seasonal to sub- and multi-decadal timescales are able to explain the internal variability of European mean summer temperatures, however their contribution for the occurrence of extreme temperatures is largely unexplored. By using the global reanalysis ERA5 and the Max Planck Institute Grand Ensemble, we show that sub-decadal (5-10yr) variability is prevalent in European summer heat extremes. We are able to link the occurrence of those heat extremes with the North Atlantic heat inertia. More specifically, in the North Atlantic, anomalies of the barotropic stream function and ocean heat content are redistributed several years prior an extreme event, thereby a affecting ocean-atmosphere heat fluxes at the time of he occurrence of heat extremes. This development is tailored by strengthening of the sub-tropical gyre, alternation of mean sea level pressure, and an associated northward jet stream displacement. The results indicate the important role of the inertia of the North Atlantic for the occurrence of heat extremes over Europe, and possibly help to improve their predictability several years ahead.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.A45K1989H