Fig. 1: Large-scale meteorological and dust response to sudden stratospheric warming events (SSWs).

a Composites of anomalous sea level pressure (SLP) (contours) and 10 m wind (arrows) during SSW episodes over the 1980/81-2013/14 extended winters (from November to March, NDJFM). The SLP and 10 m wind fields come from the MERRA2 reanalysis. Shadings indicate SLP anomalies that are statistically significant at the p < 0.10 level based on a two-tailed Monte Carlo test. Wind vectors shown are statistically significant at least for one component. Scaling for the wind vectors is given in the bottom-right corner (units: ms⁻¹). Yellow contours indicate the regressed SLP anomalies onto the extended wintertime (NDJFM) North Atlantic Oscillation (NAO) index (see Methods). To make them comparable to the composite SLP anomalies following SSWs, the regressed SLP anomalies are scaled by the average value of the NAO index during SSW episodes, which is slightly greater than −0.3 (a histogram is shown in Supplementary Fig. 1). b The corresponding extended wintertime (NDJFM) climatologies of SLP and 10 m wind fields. c, d The same as a, b but for CESM2 surface dust concentrations (units: μg m⁻³). The two red boxes in panel c indicate the Eastern Mediterranean (30°–33.75°N, 10°–30°E) and West Africa (16.25°–23.75°N, 12.5°–23.75°E) regions with large and significant dust response to SSWs. Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com.