B-15

Last season saw one of the largest icebergs ever break off the Ross Ice Shelf, near America's McMurdo station.

It was called "B-15"... 180 miles long, 22 miles wide, equivalent to the state of Massachusetts.

Image courtesy of the
National Science Foundation

Image courtesy of the
National Science Foundation

Satellites were able to track it from above... though sometimes even a giant berg got lost in thick, obscuring clouds. Researchers thought it was as much as 1300 feet deep.

In following months, the currents broke B-15 up into two huge chunks, one of which began to drift still closer to McMurdo. Both for safety and for science it was time to try to track the big bergs' movements very carefully.


Doug MacAyeal
University of Chicago
This is the largest iceberg effort ever witnessed. We'd like to know (a) what is the significance of this iceberg having calved to the Antarctic's mass balance and (b) what will this iceberg do to the ocean and the atmosphere beyond the Antarctic when it eventually drifts north.

Researchers decided to place sensors on the ice berg, to let them know precisely where it was, and the weather conditions. That's easier said than done. It required close coordination with the coast guard icebreaker, "Polar Sea."

Image courtesy of the
National Science Foundation

Image courtesy of the
National Science Foundation

Safety first, as every where in the Antarctic. Mountaineers checked for cracks and crevasses. Then a Coast Guard helicopter placed the researchers and their instruments aboard the giant floating platform. They assembled an automated weather station (AWS) which they would leave on top of the berg, which towered 20 stories, 160 feet, above the ocean. There was an anemometer, solar panels to power it during Antarctic summer, and satellite links to send back data.


Doug MacAyeal
University of Chicago
These instruments will tell us the weather conditions on B-15, the position of B-15, on an hourly basis as it gyrates and moves on a path through the Southern Ocean.


Richard Alley
Geologist/glaciologist
Penn State
The floating ice shelf there is really thick. It's hard for a big crack to get all the way through something that's a good chunk of a mile thick, and it turns out that rather than a lot of little pieces breaking off it waits a long while and then a big piece breaks off. So there'll be 50 years with no big pieces and then a couple of big pieces come out. So you see this Connecticut sized iceberg is out tromping around the North Sea, but that probably doesn't mean anything for global climate change.

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 • Images Available: Science Team Places Sensors on Enormous Iceberg to Track Motion, Weather Conditions
Article on the placement of three weather stations on B-15 to track the iceberg's movements.
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