17 April 2009

Wilkins Ice Bridge Collapse

An ice bridge connecting the Charcot Island and the Antarctic Peninsula has collapsed early April 2009 due to global warming and will allow icebergs to drift into the Southern Ocean.

Apogee tasked TerraSAR-X to acquire the first high resolution radar imagery over the Ice bridge supporting Wilkins Ice Shelf.

The image below is a ScanSAR image acquired on 13th April 2009 over Wilkins ice Shelf. The red rectangle outlining the collapsed ice bridge (seen in greater detail below) as well as two high resolution subsets.A second image was acquired on the 15th April to show ice movements and current as well as the formation of new ice suggesting that the ice debris may not be escaping into the open ocean this year.

TerraSAR-X ScanSAR over Wilkins Ice Shelf, 13 April 2009. .

The ENVISAT image below shows the ice bridge between the Charcot Island and the Antarctic Peninsula in the early stages of the collapse.

The image below shows the same subset with TerraSAR-X. The ice bridge has collapsed and broken ice will drift into the Southern Ocean.

This composite below combines the TerraSAR images taken 2 days apart, where the Red ’shadow’ shows the earlier position and the Cyan colour is the later position. The arrows show the result of the drift analysis between the two dates as the direction of currents.

The second image acquired on the 15th April 2009 is shown by itself below and reveals interesting details about the ice structures and reforming new ice.

The image subsets below show a close up of broken ice components. Some of them appear black, probably due to high water content and a smooth surface acting like a mirror. Others show texture suggesting an undulating surface which may have been caused by the effect of strong winds over time.

For further Information Contact Apogee