This 200-km subset of an ASAR wide swath image shows the marginal ice zone outside the ice shelf at Marguerite Bay on the west side of the Antarctic Peninsula.

In the centre of the image a medium-scale pair of eddies is revealed as two spiralling vortices of open water (dark backscatter) and first-year sea ice (bright backscatter). The eddies spin in opposite directions (cyclonic and anti-cyclonic). Each has a mean diameter of approximately 25 km.

These features are very common in the marginal ice zone and represent clear evidence of coupled sea-ice-ocean-atmospheric interactions.

Technical Information:
Instrument: Advanced Synthetic Aperture Radar (ASAR)
Mode: Wide Swath
Acquisition date: 18 March 2002
Orbit number: 00250
Orbit direction: Descending
Polarisation: VV
Resolution: 150 metres