Recent equatorward shift of the summer North Atlantic jet dominated by internal climate variability

Sheng, C., Methven, J. ORCID: https://orcid.org/0000-0002-7636-6872, Dong, B. ORCID: https://orcid.org/0000-0003-0809-7911, He, B., Wu, G., Zhang, P. and Liu, Y. (2026) Recent equatorward shift of the summer North Atlantic jet dominated by internal climate variability. Science Advances, 12 (28). eaee8136. ISSN 2375-2548 doi: 10.1126/sciadv.aee8136

Abstract/Summary

The North Atlantic jet (NAJ), a fast-flowing westerly wind in the upper troposphere, influences the movement of extreme weather systems and affects the safety of commercial flights. In recent decades, the summer NAJ exhibited a substantial equatorward shift over the eastern Atlantic, contrasting with the poleward shift of zonal-mean jet. However, whether this equatorward shift is driven by external forcing or internal variability remains unclear. Here, we show that the recent equatorward shift of the summer NAJ was dominated by internal climate variability. Using simulations from state-of-the-art numerical models and reanalyses, we identify the recent decadal component of the North Atlantic warming hole in summer as the key factor. Through turbulent heat release, this distinctive pattern altered the local atmospheric thermal structure, causing the shift of the summer NAJ via thermal wind response and eddy feedback. However, this internal variability–dominated situation is not expected to persist. Our results indicate that as early as the 2050s, the latitudinal shift of the summer NAJ is projected to emerge beyond the range of internal climate variability.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/131028
Identification Number/DOI	10.1126/sciadv.aee8136
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Association for the Advancement of Science
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