Interannual ice mass variations over the Antarctic ice sheet from 2003 to 2017 were linked to El Niño-Southern Oscillation

Abstract

Interannual variability in the ice mass balance over the Antarctic Ice Sheet (AIS) is closely related to atmospheric circulation and has large impact on estimating the secular trends of mass change. However, the spatiotemporal patterns of the interannual mass balance over the AIS have not been well characterized and their connection with atmospheric circulation remains unclear. To address this limitation, we applied a statistical method to three sets of mass balance data and extracted the interannual mass change signals over the Antarctic Peninsula (AP), the West Antarctic Ice Sheet (WAIS), the East Antarctic Ice Sheet (EAIS), and the whole AIS from 2003 to 2017. Our results reveal that the interannual mass variations over the AP and the WAIS displayed similar temporal patterns, characterized by an increase in 2003-2008, a decrease in 2009-2013, and an increase again in 2014-2016 (relative to the mean of the interannual mass variations in 2003-2017). The interannual mass variations over the EAIS showed opposite patterns, characterized by a decrease in 2003-2008, an increase in 2009-2013, and a decrease again in 2014-2016. These temporal patterns generated a maximum value and a minimum value; the peak-to-valley mass change was −14 Gt for the AP and −129 Gt for the WAIS while the valley-to-peak mass change was 149 Gt for the EAIS. The entire AIS did not exhibit similar patterns to the WAIS or the EAIS but demonstrated oscillations of about three years. We find that the interannual variation in precipitation is the reason for the interannual variation of the mass balance over the AIS and was highly correlated with El Niño-Southern Oscillation (ENSO) in 2003-2017. The interannual precipitation was positively correlated with ENSO in the AP (correlation=0.8) and the WAIS (correlation=0.9) but negatively correlated in the EAIS (correlation=-0.8). We also uncover that ENSO largely modulated the atmospheric circulation over the AIS and its surrounding regions. In 2009-2013 when ENSO was in strong negative phase, precipitation decreased in the AP and the WAIS but increased in the EAIS, conversely, in 2014-2016 when ENSO was in strong positive phase, precipitation increased in the AP and the WAIS but decreased in the EAIS. Overall, the opposite behaviors of precipitation in the WAIS and the EAIS under strong ENSO conditions explained the spatiotemporal patterns of interannual ice mass variations over the AIS in 2003-2017. The findings of the anti-correlation between the ENSO and the precipitation in the EAIS and the opposite temporal patterns between the WAIS and the EAIS are particularly novel and adds new insights to cryosphere studies.