Climate models may need revamping after scientists measure snow loss
Winds howling across the vast, frozen Antarctic plateaus are scouring the region of moisture by vaporizing most of the airborne snow, scientists said in a new study that could shift estimates of how much the ice-covered continent is contributing to sea level rise.
The study, published in the journal Geophysical Research Letters, suggests that as much as 90 percent of the snow that falls simply returns to the atmosphere through sublimation, turning from a solid into gas without a transitional liquid phase. According to the study, 80 billions of snow per year is ablated this way.
The study measured snow ablation in the Recovery Ice Stream in East Antarctica, where the powerful winds have removed as much as 18 meters (more than 50 feet) of snow — equal to 200 years of snow accumulation. The Recovery Ice Stream is representative of thousands of other wind-scour zones that cover about 7 percent of Antarctica.
Existing climate models haven’t accounted for the loss of snow through sublimation, and have thus overestimated surface mass by more than 80 billion tons per year.
“This impacts the surface snow accumulation estimates of most major glaciers and ice streams of East Antarctica,” said Indrani Das of the Lamont-Doherty Earth Observatory (LDEO) at Columbia University.
In most of Antarctica, climate models miss snow loss in the scour zones because they occur on a relatively small spatial scale. Higher resolution models could help measure the sublimation process more accurately.
“What we’re seeing is that East Antarctica—already among the driest regions on Earth—is a bit drier than we thought,” said Ted Scambos, lead scientist at National Snow and Ice Data Center. “It’s more likely that it is losing ice, and adding to sea level.”
Dowload a PDF copy of the study here.