![]() ![]() 3, 2019.A map shows the Halley VI research station in relation to the north rift crack. The last tracked coordinates of A-57a were 42.57S, 33.92W on Aug. “I’m not an oceanographer, but perhaps they just happened to hit exactly the right point in the Antarctic circumpolar current to shoot up north.” He added that this current usually runs from west to east, but there may have been a kink in it, or eddies, since the currents themselves generally tend to stay pretty consistent.Ĭ-02 is long gone, but as of February 1990, its last tracked coordinates (before it was too small) were 42.5S, 52.5W. Montalvo explained that most of the drifting icebergs that they are keeping an eye on are moving in the normal directions they typically see, following the currents.Īs far as why these two massive icebergs made it so far north from their home in the Antarctic, Readinger offered a guess. “We could keep tracking the smaller pieces, which are still huge,” Readinger laughed, “but we have to draw the line somewhere.” If his team tracked anything smaller, they’d be watching hundreds and maybe thousands of icebergs. This can take years or decades to happen. However, once these icebergs break apart or shrink to 20 square nautical miles (~26.5 square miles) in size, they are considered too small to continue tracking. “Antarctic icebergs are often so large they are compared to city or state sizes, such as Connecticut or Delaware.” “The southern icebergs are ridiculously massive compared to the northern ones that come from glaciers in Greenland, which are usually pretty small in comparison-around a quarter-mile square or so,” he explained. Readinger and his colleague, Sofia Montalvo, said they are currently tracking 41 icebergs in total using a combination of high-resolution visible and infrared imagery from the VIIRS sensors onboard NOAA-20 and Suomi-NPP as well as data from the Synthetic Aperture Radar (SAR) satellites, which can see through both clouds and darkness. ![]() “The icebergs are primarily ocean current-driven,” said Readinger, “but about two-thirds of the ones we are watching are actually grounded, stuck on the bottom near the shore.” In fact, A-57a actually sat right next to where it calved for years before finally drifting away. C-02 was the second iceberg to break off the C quadrant since tracking began.Īccording to Christopher Readinger, an analyst with the US National Ice Center who studies the movements of icebergs, they can float up to 200 nautical miles (roughly 230 miles) per week. It further broke into a second iceberg (A-57b), which kept breaking up and eventually deteriorated. ![]() A-57a was the 57th iceberg to break off the continent’s A-quadrant since tracking began in the early 1970s. For example, researchers divided Antarctica into four quadrants (A, B, C, and D). Around Antarctica they are named after where they originate as well as the sequential number in which they calve. Icebergs, or large pieces of ice that have broken off from a glacier or ice shelf, are a common sight in polar regions as they float (or sometimes run aground) in the frigid water. However, both made it about the same distance north, to around 42.5 degrees south latitude. Coming in at around one-third the size of C-02 (or roughly the size of Kansas City in area), this iceberg calved on from the Ronne Ice Shelf and was last seen more than 930 miles east of C-02’s last known position, which had been about 570 miles off Punta Delgada on the eastern coast of Argentina. Researchers who specialize in tracking icebergs have found a contender that is now vying for the title, named A-57a. ![]()
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