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One and a half times the size of Berlin

2021-03-01T17:08:28.728Z


An iceberg one and a half times the size of Berlin has broken off in Antarctica. The German icebreaker "Polarstern" is on the move near him. A decision has to be made there.


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The giant iceberg A74 has detached itself from the Brunt ice shelf in Antarctica

Photo: DLR

It was the longest non-stop passenger connection in Lufthansa history: at the end of January, an A350-900 took off from Hamburg for a British military base on the Falkland Islands, on board scientists from the current Antarctic expedition of the Alfred Wegener Institute (AWI) .

The record flight should bring her safely to her ship “Polarstern” even in times of pandemic.

The 50 or so experts on board the icebreaker are now on the move in the Antarctic Weddell Sea.

There, under the leadership of the expedition leader Hartmut Hellmer, they want to find out how the system of ocean, ice and living beings in the region behaves in the face of climate change - and how the situation could develop in the future.

In addition to state-of-the-art measuring devices, animal helpers are also used: up to twelve Weddell seals have sensors that measure salinity, temperature and water depth stuck to their foreheads - and thus provide real-time data from the region under the ice until the next coat change.

In the target area of ​​the expedition, large amounts of cold water from the ice shelf area, i.e. the foothills of the Antarctic glaciers floating on the ocean, meet relatively warm deep water from the north and mix.

On the one hand, this drives the global ocean circulation, on the other hand, warm deep water can attack the shelves from below.

"Our model calculations show that the ice shelf could melt more rapidly from below around the middle of our century and that the entry of inland ice could accelerate," warns Hellmer.

Around 100 nautical miles from the current area of ​​operation of the »Polarstern« a huge iceberg has now broken off the Brunt Ice Shelf, with an area of ​​1270 square kilometers it is about one and a half times the size of Berlin.

The breaking off of such large icebergs from the ice shelf is basically a normal process and not a direct consequence of man-made climate change.

Nevertheless, when a new giant mountain is born, researchers naturally take a close look to understand the processes in detail.

Research station had to move

A current picture of the German radar satellite »TerraSAR-X« from Sunday shows the floating block from space, which is listed under the abbreviation A74 in the catalogs.

The German Aerospace Center (DLR) operates the TerraSAR-X satellite, whose view is not disturbed by clouds or bad weather.

There is a separate receiving station at the tip of the Antarctic Peninsula.

Immediately after the recording, the images from the satellite are received, processed and transmitted with almost no time delay to the »Polarstern«, where they serve as a navigation aid, among other things.

"The Brunt ice shelf has been under observation for a long time," says DLR expert Paul Wachter to SPIEGEL.

The reason are cracks that had appeared years ago south of the current demolition site.

As a result of this, Great Britain had already decided to move its research station »Halley«, which specializes primarily in studying the atmosphere, to a safer position.

"After three long rifts in the Brunt Ice Shelf system had actively developed over the past five years, we all expected something spectacular to happen," said glaciologist Adrian Luckman of Swansea University, UK, in an interview with the BBC.

"Halley" is about 20 kilometers away from the current demolition edge, but the station is currently not manned anyway for security reasons.

Therefore there is no threat to human life.

On board the »Polarstern«, captain Stefan Schwarze will have to decide in the coming days whether he wants to get closer to the region from the A74 and possibly even navigate between the iceberg and the ice shelf.

Further satellite images for planning are definitely requested.

However, Schwarze is currently informing SPIEGEL: "The iceberg is not on our agenda for the time being." For the biologists among the researchers, such an excursion would be quite interesting, as they would get to see the "virgin" seabed.

The oceanographers on board, on the other hand, have already declined.

They are interested in the warm deep water that gnaws at the shelves - but they had not been able to prove that on the previous ice edge during the current expedition.

It shouldn't be found any closer to the country.

In any case, the time for a trip to the nautically demanding region would be quite limited.

According to the AWI, the icebreaker is expected in Atka Bay in the second half of March at the latest.

Among other things, the replaced wintering team from the German research station »Neumayer III« is picked up here.

Icon: The mirror

Source: spiegel

All tech articles on 2021-03-01

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