Table 1 Yearly and seasonal simultaneous correlations between Antarctic sea ice extent (SIE) and ocean/atmosphere drivers in SPEAR_MED runs

a	Annual mean correlation (30 members)
	Natural	Historical	SSP534OS	SSP585
LCS	–0.26*	–0.15*	–0.17*	–0.13*
MLD	–0.25*	0.21*	0.36*	0.29*
SAM	0.22*	0.26*	0.39*	0.35*
NINO3.4	–0.13*	–0.16*	–0.03	0.02

b	Jan–Mar correlation				c	Apr–Jun correlation
	Natural	Historical	SSP534OS	SSP585		Natural	Historical	SSP534OS	SSP585
LCS	–0.00	–0.01	0.01	0.01	LCS	–0.26*	–0.25*	–0.16*	–0.22*
MLD	0.21*	0.21*	0.15*	–0.01	MLD	–0.20*	0.50*	0.60*	0.59*
SAM	0.17*	0.18*	0.09*	0.03	SAM	0.29*	0.24*	0.30*	0.25*
NINO3.4	–0.03	–0.09*	0.03	0.02	NINO3.4	0.10*	–0.18*	–0.14*	–0.04

d	Jul–Sep correlation				e	Oct–Dec correlation
	Natural	Historical	SSP534OS	SSP585		Natural	Historical	SSP534OS	SSP585
LCS	–0.27*	–0.19*	–0.22*	–0.19*	LCS	–0.20*	–0.14*	–0.10*	–0.09*
MLD	–0.17*	0.17*	0.29*	0.24*	MLD	–0.15*	0.27*	0.50*	0.41*
SAM	0.04	0.02	0.14*	0.12*	SAM	0.30*	0.31*	0.43*	0.41*
NINO3.4	–0.12	–0.12*	0.08	0.16*	NINO3.4	–0.07	–0.08*	–0.03	–0.01

a Yearly simultaneous correlation coefficients of annual mean lower cell strength (LCS) anomaly on a density space, mixed-layer depth (MLD) anomaly, Southern Annular Mode (SAM) index, and NINO3.4 index with Antarctic SIE anomalies for 30 ensemble members of SPEAR_MED natural, historical, and SSP forcing runs. We used annual mean anomalies during 1985–2014 period for the natural and historical runs and during 2071–2100 period for the SSP forcing runs. We calculated the correlations across 30 ensemble members over the 30-year period (i.e., 900 points), not for the ensemble mean anomalies, because the ensemble-mean values represent the forced variability. Asterisk indicates statistically significant correlations that exceed 99% confidence level using Student’s t-test. b–e Same as in (a), but for January–March, April–June, July–September, and October–December mean anomalies from 30 members of SPEAR_MED natural, historical, and SSP forcing runs, respectively.

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