A new study that will be published in Journal of Geophysical Research has confirmed some bad news: the layer of snow in the Arctic region is most definitely thinning, and at a very fast rate. Scientists used data tracking the depth of snow that sits atop Arctic ice from almost a hundred years ago, and found that the snow is melting rapidly as the region warms. Thinning is worst on the ice in western Arctic waters, close to Alaska.
The study was led by NASA and the University of Washington. They analyzed data from ice buoys and data that came from NASA aircraft that have been tracking the ice snow levels in the region for the past few decades. They also looked at much older data from Soviet-era ice floes, dating back to the 1950s, so that they could compare the snow levels to pre-climate change levels and track the numbers over a much longer time span.
Soviet scientists used to record snow levels by hand, using measuring sticks while sitting on chunks of floating sea ice to track the snow in the region. Now, the scientists of this study tracked data using cameras high up on NASA aircraft, and hand-held automatic measuring systems that look like ski poles.
"When you stab it into the ground, the basket moves up, and it records the distance between the magnet and the end of the probe," said the study's lead author Melinda Webster, a graduate student at the University of Washington who is studying oceanography. "You can take a lot of measurements very quickly. It's a pretty big difference from the Soviet field stations."
Webster periodically collected data in person from the Arctic snow, using an automatic measurer to pierce the snow and find the depth of it. She measured the ground every few feet.
The research team looked at Soviet measurements dating all the way back to 1937, and a period of Soviet data from 1954 to 1991. They compared that data to NASA data collected by air from 2009 to 2013, as well as data from ice buoys collected by the U.S. Army Corps of Engineers. They found that the snow levels have gone down from 14 inches to 9 inches in the west of the Arctic region, near Alaska. Further north and west of Alaska, near the Beaufort and Chukchi seas, the snow had thinned from 13 inches to 6 inches. About a third of the snow near Alaska has declined, and almost half of the snow near the Beaufort and Chukchi seas.
"Knowing exactly the error between the airborne and the ground measurements, we're able to say with confidence, Yes, the snow is decreasing in the Beaufort and Chukchi seas," said Ignatius Rigor, an oceanographer at the University of Washington's Applied Physics Laboratory, who co-authored the paper.
The team suggested that the snow may be getting thinner because, as the oceans warm from climate change, they don't freeze until later in the year. That means that most of the region's heaviest snowfalls, which happen in the early fall, fall into the sea and melt.
The effects of this on the environment are not certain, but one side effect is that it could be damaging for animals, who use snow to build shelter.