Eight Hundred Years of North Atlantic Jet Stream Variability and its Influence on European Climate Extremes
Abstract
A recent increase in mid-latitude extreme weather events has been linked to anomalies in the position, strength, and waviness of the Northern Hemisphere polar jet stream. The latitudinal position of the North Atlantic Jet (NAJ) in particular drives climatic extremes over Europe, by controlling the location of the Atlantic storm track and by influencing the occurrence and duration of atmospheric blocking. To put recent NAJ trends in a historical perspective and to investigate non-linear relationships between jet stream position, mid-latitude extreme weather events, and anthropogenic climate change, long-term records of NAJ variability are needed. Here, we combine two tree-ring based summer temperature reconstructions from Scotland and from the Balkan Peninsula to reconstruct inter-annual variability in the latitudinal position of the summer NAJ back to 1200 CE. We find that over the past centuries, a northward summer NAJ position has resulted in heatwaves, droughts, and famines in northwestern Europe, whereas a southward position has promoted wildfires in southeastern Europe and floods in northwestern Europe. We further find an unprecedented increase in NAJ anomalies since the 1960s, which supports more sinuous jet stream patterns and quasi-resonant amplification as potential dynamic pathways for Arctic warming to influence midlatitude weather.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP42B..07T
- Keywords:
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- 4916 Corals;
- PALEOCEANOGRAPHY;
- 4920 Dendrochronology;
- PALEOCEANOGRAPHY;
- 4928 Global climate models;
- PALEOCEANOGRAPHY;
- 4932 Ice cores;
- PALEOCEANOGRAPHY