Jet stream changes since 1960s linked to more extreme weatherLeave a Comment
- Researchers used tree rings to study fluctuations in the North Atlantic jet stream over Europe and found they are increasing due to climate change
- Swings between northern and southern positions of the jet became more frequent in the second half of the 20th century
January 12, 2018 University of Arizona read full ScienceDaily article here
Increased fluctuations in the path of the North Atlantic jet stream since the 1960s coincide with more extreme weather events in Europe such as heat waves, wildfires and flooding. The new research is the first reconstruction of historical changes in the North Atlantic jet stream prior to the 20th century. By using tree rings, the researchers developed a historical look at the position of the North Atlantic jet back to 1725…
….Having a 290-year record of the position of the jet stream let Trouet and her colleagues determine that swings between northern and southern positions of the jet became more frequent in the second half of the 20th century, she said.
….When the North Atlantic Jet is in the extreme northern position, the British Isles and western Europe have a summer heat wave while southeastern Europe has heavy rains and flooding, she said.
When the jet is in the extreme southern position, the situation flips: Western Europe has heavy rains and flooding while southeastern Europe has extreme high temperatures, drought and wildfires…
…”There’s a debate about whether the increased variability of the jet stream is linked to man-made global warming and the faster warming of the Arctic compared to the tropics,” Trouet said. “Part of the reason for the debate is that the data sets used to study this are quite short — 1979 to present. If you want to see if this variability is unprecedented, you need to go farther back in time — and that’s where our study comes in.”
…[She hopes] to reconstruct the path of the North Atlantic jet stream as much as 1,000 years into the past. She is also interested in reconstructing the path of the North Pacific jet stream, which influences the climate and weather over North America.
V. Trouet, F. Babst, M. Meko. Recent enhanced high-summer North Atlantic Jet variability emerges from three-century context. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-017-02699-3