Malaspina: the iconic glacier of Alaska
Lead author Brandon Tober, a doctoral student in the UArizona Department of Geosciences and colleagues used the Arizona Radio Echo Sounder, or ARES. Previously, this instrument was used for a NASA-funded mission that recorded annual variations in the thickness of glaciers, sea ice and ice caps in Greenland, Alaska and Antarctica from between 2009 and 2021.
The aircraft’s ice-penetrating radar “X-rayed” the glacier as it traversed it from the air, creating a complete “3D body scan” of the glacier and underlying bedrock.
The data indicated that the Malaspina Glacier is mostly below sea level and has several channels cutting through its bed that go at least 21 miles from where the glacier meets the coast up to its source in the Saint Elias Mountains.
Regional overview showing the Malaspina Glacier study area.
“We can speculate that the channels, the large troughs under the glacier, direct meltwater that comes out at the coast,” Tober said in a press release.
The researchers concluded that Malaspina has the capacity to deliver 560 cubic kilometers, or 134 cubic kilometers, of ice to the ocean, assuming the ice would experience large-scale shedding. In other words, Malaspina alone has the potential to raise sea levels by 1.4 millimeters, or just about 1/16 inch.
“That may not sound like much, but to put this into perspective, all Alaskan glaciers combined contribute about 0.2 millimeters per year to global sea level rise – a rate that tops all other ice areas on Earth except for the Greenland and Antarctic ice sheets ,” Tober explained.