Abstract
Persistent fluctuations in the latitudinal position of the North
Atlantic (NATL) jet stream are associated with extreme weather
anomalies, particularly over Europe. Therefore, it is crucial to
understand how the jet stream persistence might change in response to
increased greenhouse gases to deliver useful regional climate
projections. This study examines the persistence of the North Atlantic
jet stream latitudinal fluctuations in CMIP6 and ERA5. We found that
CMIP6 models consistently overestimate the persistence compared to ERA5
during the historical period. This discrepancy appears linked to too
weak transient eddies over the NATL in CMIP6 models.
By the end of the XXI century, CMIP6 models forced with the SSP585
scenario project a reduction of the jet fluctuations persistence of
about 10% during the summer season. The evidence suggests this
reduction is linked to a slower NATL jet during the summer months.