Massive Antarctic Iceberg Spotted on NASA IceBridge Flight
NASA’s Operation IceBridge on Wednesday, November 7, flew over an iceberg that is three times the size of Manhattan. This was the first time anyone has laid eyes on the giant iceberg, dubbed B-46 by the U.S. National Ice Center, that broke off from Pine Island Glacier in late October.
Image 1 - A close-up view of the rift separating Pine Island Glacier and iceberg B-46, as seen on an Operation IceBridge flight on November 7, 2018. Credit: NASA/ Brooke Medley
Image 2 - New sea ice forms in a rift created when the B-46 iceberg broke off from Pine Island Glacier. Credit: NASA/Kate Ramsayer
On October 29, the National Ice Center, which tracks icebergs for navigation purposes, estimated the surface area of B-46 at 66 square nautical miles, though satellite imagery and the IceBridge flight showed that the main iceberg is already beginning to break up.
Ice shelves, floating glacial ice areas that surround much of Antarctica, calve icebergs as part of the natural process of ice flowing out to sea. But scientists are also watching closely to see if the frequency of calving events is changing over time. In late 2016, IceBridge saw a crack beginning across the ~ approximately 22 mile-wide trunk of Pine Island Glacier. It took a year for the rift to fully form and the iceberg named B-44 to break away in September 2017. The crack that would become B-46 was first noticed in late September 2018 and the iceberg broke away about a month later. Pine Island has now calved major icebergs in 2013, 2015, 2017, and 2018. Prior to that stretch, the glacier was experiencing major calving events about every six years.
Pine Island and nearby Thwaites Glacier alone are contributing about 1 millimeter per decade to global sea level rise, as their flow of ice to the sea has accelerated in recent years, according to NASA research.
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