Atmospheric rivers are long, narrow corridors of concentrated water vapor in the atmosphere that transport large amounts of moisture over long distances. When an atmospheric river meets varied terrain like mountains or even colder temperatures, the moisture being carried condenses, resulting in high amounts of precipitation, such as heavy rain and snowfall.
While atmospheric rivers occur regularly around the globe, their penetration into Antarctica’s interior is relatively infrequent. Because of Antarctica’s varied topography and incredibly dry conditions, detecting atmospheric rivers has always been challenging with current 2D algorithms. However, that is changing. Scientists have just developed a new 3D algorithm to detect the vertical variations within these rivers, allowing for easier and more accurate discovery.
- Related: What is An “Atmospheric River”?
This new 3D detection algorithm was tested by the 44th Japanese Antarctic Research Expedition at Dome Fuji on the East Antarctic Plateau. Developed by expanding upon the conventional 2D algorithm, the new 3D approach is able to more accurately detect these rivers despite the rugged terrain. Therefore, the algorithm is more likely to pick up on an atmospheric event, allowing scientists to predict potential storms and precipitation totals.
When tested, this 3D algorithm showed that more than half of the major precipitation events observed at Dome Fuji on the East Antarctic Plateau were from an atmospheric river. Additionally, the precipitation from these events accounted for about 40% of the total precipitation during that observation period. From 1979 to 2023, atmospheric rivers showed up on fewer than 1 in 10 days, but still supplied roughly 30% to 60% of the yearly snowfall in Antarctica’s interior. This data shows just how dominant atmospheric rivers are in affecting Antarctica’s precipitation totals — despite their rare occurrence.
With a more accurate detection algorithm, fewer atmospheric rivers will go undetected and unrecorded. Studies show that major storms within Antarctica’s interior directly resulted from an atmospheric event. Long-term trends show that atmospheric events have far more impact on major precipitation across Antarctica’s interior than scientists initially realized. Without the 3D algorithm, scientists may not have realized how far these rivers extend.
Not only do atmospheric rivers have a direct effect on annual precipitation totals, but the moisture released contributes to the growth of surface ice mass. Whether it’s rainfall or heavy snow, these events are offsetting ice loss from a warming climate. With more accurate detection, it will be easier for scientists to estimate Antarctica’s future contribution to sea-level rise.
Because rare atmospheric river events deliver so much of Antarctica’s annual precipitation totals, this new 3D algorithm is changing what scientists know about this climate. Having methods to accurately record and predict these rivers will transform how scientists are able to forecast the ice sheet’s future and global sea level change. Not to mention, they will be able to better anticipate major storms influenced by an atmospheric river.
