Jan 12, 2018

Recent enhanced high-summer North Atlantic Jet variability emerges from three-century context

by
V. Trouet, F. Babst & M. Meko
,
Nature Communications
  • States that a recent increase in mid-latitude extreme weather events has been linked to Northern Hemisphere polar jet stream anomalies
  • States that a long-term, historical perspective of jet stream variability is needed
  • Combines two tree-ring records from the British Isles and the northeastern Mediterranean to reconstruct variability in the latitudinal position of the high-summer North Atlantic Jet (NAJ) back to 1725 CE
  • Finds that northward NAJ anomalies have resulted in heatwaves and droughts in northwestern Europe and southward anomalies have promoted wildfires in southeastern Europe
  • Finds an unprecedented increase in NAJ variance since the 1960s, which co-occurs with enhanced late twentieth century variance in the Central and North Pacific Basin
  • Results suggest increased late twentieth century interannual meridional jet stream variability and support more sinuous jet stream patterns and quasi-resonant amplification as potential dynamic pathways for Arctic warming to influence mid-latitude weather