Fig. 1

Sea level pressure regressed onto the Niño3.4 SST index during boreal winter (hPa⁻¹ °C⁻¹). The colored contours show the sea level pressure (SLP) regression coefficients in a reanalysis datasets, b AMIP5 models, c AMIP6 models, d CMIP5 models and e CMIP6 models. Gray dotted areas in a–e indicate that regression coefficients are significant at the 95% confidence level. Panel f shows that the regression of the Southern Oscillation index (SOI, defined as the difference of the spatial-mean SLP between the 5° S–5° N, 160° W–80° W and 5° S–5° N, 80° E–160° E, shown as the black boxes in Fig. 1a) onto the Niño3.4 SST index in reanalyses (red bar), AMIP5/6 (deep and light green bars) and CMIP5/6 (deep and light blue bars) models. The white lines show the regression coefficients, and the ranges of the bars indicate the 95% confidence interval of these regression results with Student’s t test. g Is the box–whisker plots to indicate the spread of the reanalysis and model representation. On each box, the central line is the median, and the bottom and top edges of the box is the 25th and 75th percentiles, respectively. The whiskers extend to the most extreme data points not considered outliers. The ‘+’ symbol is the outliers in reanalyses or models