This radar image taken in 1998 shows just how much ice is covering Antarctica. Its showing a slice of 1.9 miles of ice over mountains spanning a few hundred kilometres either side of the South Pole. (The horizontal scale differs from the vertical.... those Trans-Antarctic Mountains are not that steep!)
Over many years, snow that fell at the surface has been compressed and transformed into successive layers of ice. The process continues and layers become further compressed under the tremendous weight of the ice sheet. The ice that makes up a single layer is a uniform age and contains information about the composition of the atmosphere at the time that the snow initially fell.
Radar instruments on aircraft can detect these layers by transmitting microwave signals and recording the magnitude of the echoes returned to the instrument. The method works because the strength of the echo varies depending on factors such as density and the amount of impurities in each layer.
'What Lies Below' NASA Earth Observatory
98% of the continent is covered in ice that is miles deep. In fact, 70% of the world fresh water is sitting frozen on Antarctica. For a desert, that is a lot of frozen water. And to top it off, all that ice is moving very very slowly. (Another topic for another time I think)
Want to read more about Antarctic ice thickness, you cant go wrong with the snappily titled paper 'Bedmap2: improved ice bed, surface and thickness datasets for Antarctica' published in 2013.
