Extratropical cyclones as buffers and drivers of changes in surface mass balance of the Antarctic Ice Sheet under global warming

Extratropical cyclones (ECs), crucial drivers of midlatitude precipitation, play an important role in shaping the surface mass balance (SMB) of the Antarctic Ice Sheet (AIS). However, the influence of global warming on the change of EC’s contribution to the SMB remains uncertain. Through a series of idealized simulations involving increased sea surface temperatures and reduced AIS surface elevations, this study reveals that warming tends to shift ECs poleward. This shift amplifies cyclone track density around the AIS, leading to enhanced EC-induced precipitation, predominantly as snow. This additional snowfall offsets some AIS melting induced by warming. Yet, as surface temperatures rise, particularly during the austral summer with reduced AIS elevations, the protective effect diminishes due to increased runoff and rainfall when AIS elevation decreases to 25% of its original height. These findings illuminate the dual role of ECs in moderating and exacerbating AIS mass loss under future warming scenarios, offering critical insights into their impact on the AIS's long-term evolution.