Source: Journal of Geophysical Research: Atmospheres
Stratosphere-troposphere coupling is an important source of surface climate variability, especially as related to the wintertime stratospheric polar vortex. Evolution of the coupling in future climates depends on vortex changes, but climate models have not agreed on whether the polar vortex will strengthen or weaken in the future.
Karpechko et al.  explore future changes of the Northern Hemisphere polar vortex and its influence on regional tropospheric climate, including precipitation and winter cold extremes, using state-of-the-art climate models. The analyses point out large differences in projections of future vortex strength among models even with high-emissions global warming scenarios, so that uncertainties have not been reduced in the new generation models. Modeled vortex changes are echoed in coupling with surface climate, indicating a source of uncertainties for projecting regional climate impacts. While it has minor influence on the troposphere, these results highlight a robust eastward shift of the polar vortex in an evolving climate.
Citation: Karpechko, A. Y., Afargan-Gerstman, H., Butler, A. H., Domeisen, D. I., Kretschmer, M., Lawrence, Z., et al. (2022). Northern Hemisphere Stratosphere-Troposphere Circulation Change in CMIP6 Models. Part 1: Inter-Model Spread and Scenario Sensitivity. Journal of Geophysical Research: Atmospheres, 127, e2022JD036992. https://doi.org/10.1029/2022JD036992
—William J. Randel, Editor, Journal of Geophysical Research: Atmospheres; and Gang Chen, Associate Editor, Journal of Geophysical Research: Atmospheres