Atmospheric Rivers May Add Snowy Mass to Antarctica's Melting Ice Sheet

Extreme weather phenomena called atmospheric rivers may be behind the intense snowstorms that were recorded in 2009 and 2011 in East Antarctica. Scientists have taken a closer look at these storms and have found that this snow accumulation partly offset recent ice loss from the Antarctic ice sheet.

Atmospheric rivers are long, narrow water vapor plumes that stretch thousands of kilometers across the sky over vast ocean areas. These rivers are capable of rapidly transporting large amounts of moisture around the globe, and can cause devastating precipitation when they hit coastal areas. While they're mostly known for their flood-causing impact in Europe and the Americas, they're also important in Earth's polar climate.

In this latest study, the researchers used a combination of advanced modeling techniques and data from a polar research station in order to create the first ever in-depth look at how atmospheric rivers affect precipitation in Antarctica.

In the end, they found two particular instances of heavy snowfall in the East Antarctic region were caused by these rivers. One in May 2009 and another in February 2011 caused a good 22 percent of total annual snow accumulation in those years.

"When we looked at all the extreme weather events that took place during 2009 and 2011, we found that the nine atmospheric rivers that hit East Antarctica in those years accounted for 80 percent of the exceptional snow accumulation at Princess Elisabeth station," said Irina Gorodetskaya, one of the researchers, in a news release.

The findings reveal a bit more about how the global water cycle is affected by atmospheric rivers. This, in turn, may allow researchers to improve their models of the rate of melting in polar regions.

"Our results should not be misinterpreted as evidence that the impacts of global warming will be small or reversed due to compensating effects," said Gorodetskaya. "On the contrary, they confirm the potential of Earth's warming climate toe manifest itself in anomalous regional responses. Thus, our understanding of climate change and its worldwide impact will strongly depend on climate models' ability to capture extreme weather events, such as atmospheric rivers and the resulting anomalies in precipitation and temperature."

The findings are published in the journal Geophysical Research Letters and Science.

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