Antarctic giant on the loose
21 January 2005
This animated flyover is based on Envisat acquisitions. See the full version (Windows Media Player, 3 Mb).
The first phase is rendered using a single MERIS false-colour image from 22 January 2004, given vertical relief using a terrain model. It begins with a westerly flight over austral summer sea-ice pack in the Southern Ross Sea, arriving at the solid white border of fast ice fringing Victoria Land. It moves inland before circling, turning eastward over the Trans-Antarctic mountains before returning northwards. The peak of Mount Erebus on Ross Island passes beneath. The MERIS image zooms out to provide a view of the cluster of large icebergs grounded on the northeast shore of Ross Island.
The second phase returns four months in time to a series of 13 ASAR radar images illustrating the breakup of iceberg B-15A acquired during 11 Sept - 1 Jan 2004. In March 2001, B15A collided with iceberg C-16 and ran aground on Ross Island. With the underside of its southern end perched on the bottom and its northern end floating, the vertical motion of the tides and waves forced iceberg B15-A to repeatedly bend in the middle, eventually splitting in the middle along a zig zag fracture. The northernmost of the two large icebergs pieces is then observed to bump into southernmost C-19, with small knife-like B-15K shearing off during the collision.
The image fades back to MERIS, providing a perspective view of the Victoria Land coast. The flight resumes in a northerly direction as far as the Erebus ice tongue, highlighted as the MERIS image blends into the ASAR radar image. Since the ASAR radar is extremely sensitive to the difference in salty sea-ice and pure glacial ice, the radar image clearly delineates it, unlike in MERIS. The scene rotates to show various ice piers, turning further to look back to Ross Bay before rising to give a true satellite view.
This annotated ASAR image from 10 January 2005 is orientated in a northerly direction along McMurdo Sound and shows the position of the Drygalski ice tongue as well as icebergs B-15A, B-15J, C-16, the knife-like B-15K and the US McMurdo base.