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Supplementary Materials: The Weakening of the Stratospheric Polar Vortex

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and the Subsequent Surface Impacts as Consequences to Arctic Sea-ice Loss34

Yu-Chiao Liang1,2,3*, Young-Oh Kwon2, Claude Frankignoul2,4, Guillaume Gastineau4, Karen L.

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Smith5, Lorenzo M. Polvani3,6,7, Lantao Sun8, Yannick Peings9, Clara Deser10, Ruonan Zhang11,

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and James Screen1278

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Department of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan

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Woods Hole Oceanographic Institution, Woods Hole, MA, USA

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Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA

114Sorbonne Université, CNRS/IRD/MNHN, LOCEAN/IPSL, Paris, France

125Department of Physical and Environmental Sciences, University of Toronto Scarborough,

13Toronto, Ontario, Canada

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Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA

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Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY,

16USA

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Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA

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Department of Earth System Science, University of California, Irvine, CA, USA

1910National Center for Atmospheric Research Climate & Global Dynamics, Boulder, CO, USA

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Department of Atmospheric and Oceanic Sciences & Institute of Atmospheric Sciences, Fudan

21University, Shanghai, China

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12College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK

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24*Correspondence to Yu-Chiao Liang: yuchiaoliang@ntu.edu.tw

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Submit to Journal of Climate

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FIG. S1. JJA present ensemble-mean SST for AMV+/IPV- state (a) and AMV-/IPV+ state (b).

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FIG. S2. As in Figure S1 but for SON.

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FIG. S3. As in Figure S1 but for DJF.

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FIG. S4. As in Figure S1 but for SON.

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FIG. R7. The standard deviation of the global-mean SST time series during 1985-2014 period

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from CESM2-CAM6 and CESM2-WACCM6 historical simulations.

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FIG. S6. December wavenumber1 Z300 response to (a) strong SIC forcing and (b) weak SIC

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December.

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FIG. S7. December wavenumber2 Z300 response to (a) strong SIC forcing and (b) weak SIC

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forcing (color shadings). The contour lines represent the climatological wavenumber2 Z300 in

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December.

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FIG. S8. January Z50 (a)-(b), responses to strong sea-ice forcing during AMV+/IPV- and AMV-106

/IPV+ states, respectively. (c) (a) minus (b). (d)-(f) as in (a)-(c) but to weak sea-ice forcing. The

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black dots denote the field significance, while the cyan dots the 5% local significance.

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FIG. S9. January Z500 (a)-(b), responses to strong sea-ice forcing during AMV+/IPV- and AMV-

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/IPV+ states, respectively. (c) (a) minus (b). (d)-(f) as in (a)-(c) but to weak sea-ice forcing. The

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black dots denote the field significance, while the cyan dots the 5% local significance.

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FIG. S10. January SLP (a)-(b), responses to strong sea-ice forcing during AMV+/IPV- and AMV-130/IPV+ states, respectively. (c) (a) minus (b). (d)-(f) as in (a)-(c) but to weak sea-ice forcing. The

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black dots denote the field significance, while the cyan dots the 5% local significance.

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