Fig. 3: Effects of Arctic sea ice on ICP autumn precipitation and circulation.

a Regressions of 200 hPa wave activity flux (vectors, m² s⁻²) and geopotential height (shading, gpm), and b 500–200 hPa temperature anomalies (°C) against SICI (−1). c Heatmap of correlation coefficients between SICI and NAT, u200pc1, SLC, SH_N, SH_wy, MDI, and PI. Regressions of d 200 hPa zonal wind anomalies (shading, m s⁻¹), e 500 hPa, and f 850 hPa wind vectors (m s⁻¹) and geopotential height (shading), and g vertically integrated water vapor flux (vectors, kg m⁻¹ s⁻¹) and its divergence (shading, kg m⁻¹ s⁻¹) against SICI (−1). The red solid lines in a and e denote the climatological SAH and WPSH, respectively. The dark blue box in a marks the Rossby wave source region, while the light blue box indicates the ICP precipitation key region. The dashed line in b shows the climatological temperature, and the two dark blue boxes in b indicate the regions used for SLC calculation. The symbols “***”, “**”, and “*” in c denote significance at the 99%, 95%, and 90% confidence levels (t-test), respectively. The black solid line in d indicates the climatological 200 hPa jet core (>20 m s⁻¹). Black arrows in a, e, f, g denote vectors passing the 90% significance test. Dotted areas indicate values statistically significant at the 90% confidence level.