The role of atmospheric rivers for extreme ablation and snowfall events in the Southern Alps of New Zealand

Geophysical Research Letters (2019)

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2018GL081669

New Zealand glaciers are very sensitive to climate variation and change—yet relatively little is known about the individual weather patterns that cause extreme ablation and accumulation events.

Similarly, while the importance of atmospheric rivers (ARs) for extreme weather events in New Zealand is generally recognized, their importance for glacier mass balance has not been studied before.

ARs are long, narrow corridors of very high atmospheric water vapor transport, with volumetric flow rates equivalent to the world’s largest rivers.

Here we show (for the first time) that ARs do play a key role for glacier mass balance in New Zealand. Importantly, we also show that some common methods for identifying ARs do not capture all of the most extreme ablation and melt events—even though they are driven by water vapor transport rates equivalent to conventionally defined ARs.

As such, past studies have likely underestimated the importance of AR‐type events, both in New Zealand and elsewhere.