TerraSAR-X image: Coastal cliffs of Christmas Island

In the image acquired with the German Aerospace Center TerraSAR-X radar satellite, one thing is clear - even today, tropical rainforest proliferates on the island and the coastal cliffs continue to make life difficult for mariners.

Christmas Island, which belongs to Australia, has principally been of interest in the past for its phosphate deposits - hence, its ownership has shifted from Britain to Japan, then back to Britain and finally to Australia.

The island is surrounded by some 80 kilometres of cliffs. The choppy waters of the surf on the south coast are not easy to image clearly for the radar on TerraSAR-X - the waves reflect the radar signals back to the satellite very irregularly.

It looks different in the bay between the only harbour on the island, Flying Fish Cove in the northeast, and West White Beach in the northwest: "When the image was acquired on 26 November 2012, the water there was apparently calm," explains mission manager Stefan Buckreuss from the DLR Microwaves and Radar Institute.

"The smooth surface reflects the signals away from the satellite, so it appears as a dark surface."