Fig. 8: Stratospheric polar vortex response to future sea-ice loss.

a 200-year simulated differences of wintertime (December–January–February) EP fluxes (purple arrows; scaled by air pressure; the vertical component is scaled by 10⁴ and the meridional component is scaled by 10⁶; m s⁻²) of zonal wave 1–2 and their divergence (shading; scaled by air pressure; s⁻²) between the atmosphere-only BKS future and present-day SIC simulations (atm_fut minus atm_pd). b The same as (a), but for the coupled BKS future and present-day SIC simulations (cpl_fut minus cpl_pd). c The differences between b and a (b minus a). d–f are the same as (a–c), but for wintertime zonal-mean zonal wind (m/s). Purple contours in (d–f) denote the climatological wintertime zonal-mean zonal wind derived from d atm_pd and e, f cpl_pd simulations, with solid/dashed lines denoting positive/negative values. Black stippling denotes the statistical significance at the 95% confidence level according to bootstrap resampling.