Antarctica is the driest continent on Earth. The rare snowfall events on the cold Antarctic desert usually come from so-called atmospheric rivers, the same type of systems that bring winter precipitation along the western coasts of the American continents, such as the Pacific Northwest in the United States. Here we estimate how much precipitation on Antarctica is associated with these atmospheric rivers. Even though they only occur a few days per year, atmospheric rivers explain around 13% of the total Antarctic precipitation. Even more importantly, we find a strong link between year-to-year variations in Antarctic precipitation and atmospheric rivers, underlining the importance of these systems for understanding current and future changes in the Antarctic ice sheet's contribution to global sea level rise.
Atmospheric rivers contribute around 13±3% of the total Antarctic Ice Sheet (AIS) precipitation each year. The relative contribution of ARs to precipitation is most substantial in East Antarctica. ARs explain a large fraction (35%) of interannual variability in AIS precipitation.
This study combines a polar-specific AR detection algorithm with MERRA-2 precipitation rates to quantify the contribution of ARs to Antarctic snowfall. Integrated over the ice sheet, ARs contribute around 13% to Antarctic snowfall. The contribution varies substantially from year to year and on a regional (glacier basin) scale but is relatively constant throughout the seasons and across elevations. These results provide a 41-year-long, spatially continuous record of AR precipitation in Antarctica. Given the substantial interannual variability of AR frequency and their precipitation impacts, this work can help provide a broader context to the short-term, limited-area contribution of ARs to annual precipitation in Antarctica.