Satellite Measures Thickness Of World's Biggest Iceberg As It Moves Towards Open Waters

Satellite has measured the thickness of the world's biggest iceberg, A23a. The measurements revealed that the frozen block has a total average thickness of just over 280 m (920 ft), BBC reported. 

The frozen block has a known area of 3,900 sq km (1,500 sq miles), which gives it a mass of around a trillion tonnes. It is approximately 40 miles wide, meaning it stretches for as far as the eye can see, the media outlet reported. 

After being stuck to the ocean floor for over 30 years, the world's biggest iceberg, A-23a, is finally on the move! The iceberg, which broke off from the Antarctic coastline in 1986, had been grounded in the Weddell Sea, but it has now broken free and is drifting towards warmer waters.

Researchers suggest that it has reached a crucial juncture in its journey, and the forthcoming weeks are expected to determine its future path across the Southern Ocean.

The measurements of A23a come from the European Space Agency's CryoSat-2 mission, BBC reported. 

Equipped with a radar altimeter, this seasoned spacecraft can detect the portion of an iceberg's mass above the waterline. By leveraging data on the density of ice, it becomes feasible to ascertain the extent of submersion.

"Altimetry satellites like CryoSat-2, which measure the distance to the iceberg surface and the sea surface, allow us to monitor iceberg thickness from space," Dr Anne Braakmann-Folgmann, from the University of Tromso - The Arctic University of Norway, told BBC News.

"They also enable us to watch the iceberg thinning as it gets exposed to warmer ocean waters.

"And together with knowledge of the sea-floor topography, we know where an iceberg will ground or when it has thinned enough to be released again."

CryoSat indicates one section, in particular, has a very deep keel, which in 2018, had a draft - the submerged portion of an iceberg - of almost 350m, the media outlet reported.

Satellite imagery reveals surface crevasses that formed directly over the keel due to the intense collision with the sea floor.

"Over the last decade, we have seen a steady 2.5m per year decrease in thickness, which is what you would expect given the water temperatures in the Weddell Sea," Dr Andy Ridout, from University College London and the Natural Environment Research Council Centre for Polar Observation and Modelling, said.

Having arrived at the Antarctic Peninsula's tip, A23a encounters a convergence of swift water streams that circulate clockwise around the continent. Its interaction with these currents, along with the prevailing westerly winds in the region, will dictate the subsequent path of this colossal iceberg. Anticipated to follow a route known as "iceberg alley," it is poised to head towards the British overseas territory of South Georgia.