понедельник, 22 апреля 2019 г.

A Surprising Surge at Vavilov Ice CapAfter moving quite slowly…

A Surprising Surge at Vavilov Ice Cap

After moving quite slowly for decades, the outlet glacier of Vavilov Ice Cap began sliding dozens of times faster than is typical. The ice moved fast enough for the fan-shaped edge of the glacier to protrude from an ice cap on October Revolution Island and spread widely across the Kara Sea. The Landsat images above were acquired on July 1, 2013, June 18, 2015, and June 24, 2018, respectively.

“The fact that an apparently stable, cold-based glacier suddenly went from moving 20 meters per year to 20 meters per day was extremely unusual, perhaps unprecedented,” said University of Colorado Boulder glaciologist Michael Willis. “The numbers here are simply nuts. Before this happened, as far as I knew, cold-based glaciers simply didn’t do that…couldn’t do that.”

Willis and his colleagues are still piecing together what triggered such a dramatic surge. They suspect that marine sediments immediately offshore are unusually slippery, perhaps containing clay. Also, water must have somehow found its way under the land-based part of the glacier, reducing friction and priming the ice to slide.

Full story here: go.nasa.gov/2Z931lc

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