Drivers of Antarctic Extreme Precipitation Events

Antarctica is the larger of Earth's two ice sheets and holds the ice volume equivalent of ~58m of global sea level rise. In the past four decades, Antarctica lost ice at an accelerating pace and contributed to global sea level rise. Snowfall over Antarctica adds mass to the ice sheet and thus mitigates Antarctica's contribution to sea level rise. Extreme precipitation events are responsible for ~70% of the interannual variability of Antarctic precipitation and are thereful vital in understanding current and future changes in Antarctic mass balance. Here, we examine the atmospheric mechanisms, including atmospheric rivers (ARs), modulating Antarctic snowfall. We leverage MERRA-2 reanalysis and employ a combination of traditional synoptic meteorology and machine learning methods to identify drivers of extreme Antarctic precipitation events at regional and circumpolar scales. Consistent with previous research we find that extreme Antarctic precipitation occurs as a result of poleward moisture fluxes lifted by the steep Antarctic coast. Our work sheds light on the dynamic mechanisms modulating these precipitation events, including but not limited to global teleconnections, synoptic-scale cyclones, and blocking anticyclones.