Fig. 6: Large-scale circulation responses to historical sea-ice loss.

a Regression map of early-winter (November–December) BKS SIC against late-winter (January–February) 0°–150°E-mean zonal-mean air temperature (shading; K) and zonal wind (purple contours, with solid/dashed lines denoting positive/negative values; m s⁻¹) during 1979–2019, scaled by the early-winter BKS SIC difference between BKS low- and high-SIC years. b 200-year simulated differences of late-winter 0°-150°E-mean zonal-mean air temperature (shading) and zonal wind (purple contours) between the atmosphere-only historical BKS low- and high-SIC simulations (atm_lo minus atm_hi). c The same as (b), but for the coupled historical BKS low- and high-SIC simulations (cpl_lo minus cpl_hi). d The differences between c and b (c minus b). e–h, i–l are the same as (a–d), but for SLP (Pa; shading), 250-hPa Rossby wave flux (m² s⁻²; purple vector) and 500-hPa geopotential (gpm; with zonal mean removed), respectively. Purple contours in (i–l) denote the climatology of i ERA-5 1979–2019 reanalysis, j atm_hi and k, l cpl_hi, respectively (with zonal mean removed; solid/dashed line denotes positive/negative values). Black stippling denotes the statistical significance at the 95% confidence level according to bootstrap resampling.