Ice Velocity in Southeastern Alaska

In Alaska and Canada’s Yukon Territory most glaciers are so remote that speedup events can go unnoticed for months until a pilot flies over the region and reports disrupted ice, notes Mark Fahnestock of the University of Alaska. This visualization, based on an analysis by GoLIVE investigators, shows the velocity of ice in southeastern Alaska near Malaspina and Hubbard glaciers.

“By measuring ice flow all the time, we can identify a surge as it starts, providing an entirely new way to follow this phenomenon,” Fahnestock said. “We can also follow large seasonal swings in tidewater glaciers as they respond to their environment. Scientists need to see all of this variability in order to identify trends.”

Automation has been key to this ice velocity mapping effort. Landsat 8 collects images of roughly 700 sunlit parcels of the planet every day; over the course of 16 days, it observes the entire land surface of Earth in multiple visible and infrared wavelengths. This means scientists can view changes in the same spot on Earth every 16 days, or 32, 48, 64, etc., as cloud cover allows.

High-resolution Image

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