Earth from Space: Icebreaker event

March 5, 2010
Credit: ESA (Click "Enlarge" for animation)

( -- This animation, made up of eight Envisat radar images, shows the 97-km long B-9B iceberg (right) ramming into the Mertz Glacier Tongue in Eastern Antarctica in early February. The collision caused a chunk of the glacier?s tongue to snap off, giving birth to another iceberg nearly as large as B-9B.

The new iceberg, named C-28, is roughly 78-km long and 39-km wide, with a surface area of 2500 sq km (the size of Luxembourg).
Since the collision, the two icebergs have drifted together into a polynya, which is an area of open water surrounded by . Polynyas produce dense, cold, and salty water - known as 'bottom water' - that sinks to the sea bottom and drives .

There is concern that if the icebergs stay in the polynyas area, they could block the formation of the bottom water. This would mean less oxygen going into the deep currents that feed the oceans and would have implications for marine life in the region.

The Mertz Glacier, 72-km long and about 32-km wide, flows into the off East along the George V Coast. It forms a 160-km floating tongue that extends northward into the ocean in the general direction of Australia. The tongue had large cracks (visible) that developed years before the collision.

B-9B broke off the B9 iceberg that calved from the Ross Ice Shelf in West Antarctica in 1987. It drifted westwards and in 1992 ran aground less than 100 km to the east of the Mertz Glacier Tongue, where it has remained until last month. The image to the right shows the positions of the Mertz Glacier Tongue and the B-9B iceberg in December 2007.

The National Ice Center, located in Maryland, U.S., names icebergs that are at least 10 nautical miles (or 19 km) long and are located within a set distance from the . The names are assigned according to where and when they first broke off from a glacier or ice shelf. The first letter represents one of the four longitudinal quadrants of Antarctica ranging from A to D; quadrant A faces the southern tip of South America, while quadrant C faces Australia.

A sequential number is then assigned to the iceberg, corresponding to how many named icebergs have emerged from a particular quadrant since 1976. So, C-28 was given its name because it is the 28th to form in the C quadrant.

’s Advanced Synthetic Aperture Radar (ASAR) acquired these images from 10 February to 4 March in Wide Swath Mode, providing spatial resolution of 150 m. ASAR can pierce through clouds and local darkness and is capable of differentiating between different types of ice.

Explore further: Two huge icebergs let loose off Antarctica's coast

Related Stories

Two huge icebergs let loose off Antarctica's coast

February 26, 2010

(AP) -- An iceberg about the size of Luxembourg that struck a glacier off Antarctica and dislodged another massive block of ice could lower the levels of oxygen in the world's oceans, Australian and French scientists said ...

New collision looks imminent for B-15A iceberg

May 18, 2005

The mammoth B-15A iceberg appears poised to strike another floating Antarctic ice feature, a month on from a passing blow that broke off the end of the Drygalski ice tongue. As this Envisat image reveals, this time its target ...

Birth of an iceberg

October 19, 2007

New images, acquired by Envisat’s Advanced Synthetic Aperture Radar (ASAR) instrument, show the breaking away of a giant iceberg from the Pine Island Glacier in West Antarctica. Spanning 34 km in length by 20 km in width, ...

Envisat Captures Splitting iIceberg

March 14, 2008

Envisat captures the break up of the massive A53A iceberg located just east of the South Georgia Island (visible at image bottom) in the southern Atlantic Ocean.

Mammoth iceberg could alter ocean circulation: study

February 25, 2010

An iceberg the size of Luxembourg knocked loose from the Antarctic continent earlier this month could disrupt the ocean currents driving weather patterns around the globe, researchers said Thursday.

Recommended for you

Mountain glaciers shrinking across the West

October 22, 2017

Until recently, glaciers in the United States have been measured in two ways: placing stakes in the snow, as federal scientists have done each year since 1957 at South Cascade Glacier in Washington state; or tracking glacier ...

Carbon coating gives biochar its garden-greening power

October 20, 2017

For more than 100 years, biochar, a carbon-rich, charcoal-like substance made from oxygen-deprived plant or other organic matter, has both delighted and puzzled scientists. As a soil additive, biochar can store carbon and ...

Cool roofs have water saving benefits too

October 20, 2017

The energy and climate benefits of cool roofs have been well established: By reflecting rather than absorbing the sun's energy, light-colored roofs keep buildings, cities, and even the entire planet cooler. Now a new study ...


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Mar 05, 2010
I see from the animation that B-9B hits at the 'top' of the ice tongue - but it breaks off at the bottom.

Is there and explaination for that?
not rated yet Mar 05, 2010
croghan27: I do not have a definite answer for you, but it appears that the crack where the iceberg broke was there already. They mention in the text: "The tongue had large cracks (visible) that developed years before the collision." Looking at the first frame of the sequence the crack is visible and then opens up. I suspect that the B-9B iceberg acted as a force on the tongue "lever" that opened the crack forming the new iceberg C-28. Once open the new iceberg was free from the tongue it was able to float away with B-9B.
1 / 5 (1) Mar 05, 2010
That sounds like a reasonable mechanism.
I wonder if there is any data relating to the numbers, persistence, and perambulations of these named icebergs over the past few decades? Numbers increasing? Decreasing? Steady?
Pretty awe-inspiring that you could be out boating and encounter a piece of ice the size of Rhode Island. You could camp out on it. Invite your friends and have a party!
not rated yet Mar 06, 2010
I wonder what pros and cons there would be if one would tow smaller icebergs for example to cost of Africa to provide non-salty water to locals? Has anybody done feasibility study about that? Normal desalination is energy hungry and leaves the accuisition site with higher salinity. Iceberg mining would provide less salty local spot because of solar induced melting. That effect could be used to melt the ice at the top of iceberg just by cowering suitable area with dark 'cloth' and then letting the melt water to flow downwards to shore by gravity through suitable piping. First of course one would need to tow/push the iceberg to suitable shore by some big tugboats.
not rated yet Mar 06, 2010
Alternatively one could put a big 'plastic bag' underside and around an iceberg and let it melt into that. Then water tankers could be used to transfer the resulting bagged melt water to shore where it could be desalinated if not done already at the iceberg by solar power.
not rated yet Mar 06, 2010
Towing has been though of long before this. Go here:

for an instance. Don't know if there was any follow up or what the French investigation concluded.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.