Contribution of Atmospheric Rivers to Antarctic Precipitation

• Published in: Geophysical research letters 2022-09, Vol.49 (18), p.e2022GL100585-n/a
• Main Authors: Maclennan, Michelle L., Lenaerts, Jan T. M., Shields, Christine, Wille, Jonathan D.
• Format: Article
• Language: English
• Subjects: Algorithms; Antarctic ice sheet; Antarctic precipitation; Antarctica; Atmospheric moisture; atmospheric rivers; detection; ENVIRONMENTAL SCIENCES; Extreme weather; Glaciation; Global sea level; ice sheet mass balance; Ice sheets; Mass balance; Moisture effects; Precipitation; Rivers; Sea level changes; Sea level rise; Snowfall; surface mass balance; Variability; Winter precipitation
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2022GL100585

Atmospheric rivers (ARs) are efficient mechanisms for transporting atmospheric moisture from low latitudes to the Antarctic Ice Sheet (AIS). While AR events occur infrequently, they can lead to extreme precipitation and surface melt events on the AIS. Here we estimate the contribution of ARs to total Antarctic precipitation, by combining precipitation from atmospheric reanalyses and a polar‐specific AR detection algorithm. We show that ARs contribute substantially to Antarctic precipitation, especially in East Antarctica at elevations below 3,000 m. ARs contribute substantially to year‐to‐year variability in Antarctic precipitation. Our results highlight that ARs are an important component for understanding present and future Antarctic mass balance trends and variability. Plain Language Summary Antarctica is the driest continent on Earth. The rare snowfall events on the cold Antarctic desert usually come from so‐called atmospheric rivers (ARs), 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 ARs. Even though they only occur a few days per year, ARs 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 ARs, underlining the importance of these systems for understanding current and future changes of the Antarctic ice sheet contribution to global sea level rise. Key Points Atmospheric rivers (ARs) 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