Fig. 1: RICE glacial records between 40 and 26 ka BP.

a nssCa^{2+ 20}, b ssNa⁺ (this study), c δD¹⁹. Antarctic Isotope Maxima (AIM) events identified in RICE δD are shown in gray bars and are numbered at the bottom. Downward arrows in nssCa²⁺ indicate the lowering of concentration during AIM events and arrows pointing upwards in ssNa⁺ indicate an increase in concentration during AIM events. Black bold lines indicate the timing and magnitude of the mean shift. Thick brown and redline indicate a 50-yr average of the original nssCa²⁺ and Na⁺ data, respectively. δD is sampled on a 50-yr interval and smoothed using a 500-yr low pass filter. The latitudinal position of Southern Hemisphere Westerly Winds (SHWW) inferred from nssCa²⁺ concentration is shown using an arrow on the right side adjacent to the nssCa²⁺ plot. The direction of spatial change in the open-ocean area based on the Na⁺ level is shown by an arrow on the left side adjacent to Na⁺ plot. Higher δD values indicate atmospheric warming. Marine isotope stages (MIS) bracketed in this interval are shown using yellow and green bars at the top. The numbering of the events is based on WAIS Divide Ice Core (WDC)³¹. Source data are provided as a Source Data file.